Device match

[fangrui166]

uint8_t base_addr_0[4] = {0xE7, 0xE7, 0xE7, 0xE7};
uint8_t base_addr_1[4] = {0xC2, 0xC2, 0xC2, 0xC2};
uint8_t addr_prefix[8] = {0xE7, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8 };

i want to triger a interrupt via PPI when received package from pipe 2 ( 0xC3 0xC2, 0xC2, 0xC2, 0xC2). so how can I config DAB , DAP and DACNF registers ?

my PPI init like below, if it is correct ?

nrf_drv_gpiote_init();

nrf_drv_gpiote_out_config_t config = GPIOTE_CONFIG_OUT_TASK_TOGGLE(false);
nrf_drv_gpiote_out_init(LED_4, &config);
uint32_t gpiote_task_addr = nrf_drv_gpiote_out_task_addr_get(LED_4);

NRF_RADIO->DAB[?] = ?
NRF_RADIO->DAP[?] = ?
NRF_RADIO->DACNF |= ?

NRF_PPI->CH[NRF_ESB_PPI_POS_SYNC].EEP = (uint32_t)&NRF_RADIO->EVENTS_DEVMATCH;
NRF_PPI->CH[NRF_ESB_PPI_POS_SYNC].TEP = (uint32_t)gpiote_task_addr;
NRF_PPI->CHENSET = (1 << NRF_ESB_PPI_POS_SYNC) ;

nrf_drv_gpiote_out_task_enable(LED_4);

[Sigurd]

Hi,

You will need to add your own 48 bit device address to the payload to use this for ESB. From the infocenter we have the following:

The Device Address match unit assumes that the 48 first bits of the payload is the device address and that bit number 6 in S0 is the TxAdd bit.

From the BLE Spec, we have the following:

The TxAdd in the advertising channel PDU header indicates whether the advertiser’s address in the AdvA field is public (TxAdd = 0) or random (TxAdd = 1).

So you can do whatever you want with this field for non-BLE communication, i.e. you can choose if you want to use 0 or 1, just make sure that DACNF register is configured accordingly, based on what you set the bit number 6 in S0 to.

You can find an example on how to configure these registers in the zephyr github, here is a link.

[fangrui166]

Sigurd said:

You will need to add your own 48 bit device address to the payload to use this for ESB. From the infocenter we have the following:

do you mean "48 bit device address' is "base address and prefix address" ? and it is corresponding to the picture of "ADDRESS" ?

[Sigurd]

In case you still need to use the Device Address match unit, we will create an example for you.

[Sigurd]

Hi,

On the transmitter side we need to add a random 48-bit device address to the payload field. I will use pipe 0 in this example code and this random 6 byte device address.

static nrf_esb_payload_t        tx_payload = NRF_ESB_CREATE_PAYLOAD(0, 0x24, 0x46, 0x67, 0x11, 0x88, 0x43);

The Device Address Match unit will only work when the RADIO is configured for little endian. By default ESB uses big endian, so we need to change the endian. In the file nrf_esb.c, we need to change the function update_rf_payload_format_esb_dpl() and update_rf_payload_format_esb(). These functions configures the NRF_RADIO->PCNF1 register, and here we need to change RADIO_PCNF1_ENDIAN_Big to RADIO_PCNF1_ENDIAN_Little.

In the main() while-loop on the transmitter, we should remove the part where we are changing the payload and instead just toggle LED_1, i.e. so that the if else statement looks like this:

 

        if (nrf_esb_write_payload(&tx_payload) == NRF_SUCCESS)

        {

                                             nrf_gpio_pin_toggle(LED_1);

        }

        else

        {

            NRF_LOG("Sending packet failed\r\n");

        }

On the receiver side, we need to configure the Device Address match unit with the Device Address the transmitter have inserted in the payload. Let’s create a function called radio_whitelist_add(), that we can use the configure the registers. This function could look like this:

void radio_whitelist_add(uint8_t pipe, const uint8_t * addr)

{

  NRF_RADIO->DAP[pipe] = ( (((uint16_t)addr[5]) <<  8)

                          | (((uint16_t)addr[4]))     );

 

  NRF_RADIO->DAB[pipe] = ( (((uint32_t)addr[3]) << 24)

                          | (((uint32_t)addr[2]) << 16)

                          | (((uint32_t)addr[1]) <<  8)

                          | (((uint32_t)addr[0]))     );

 

    NRF_RADIO->DACNF |= (1U << (pipe + RADIO_DACNF_TXADD0_Pos));

    NRF_RADIO->DACNF |=  (1U << pipe);

}

Let’s store the device address we will be using(same as we used in the transmitter).

static uint8_t const m_adv_addr[]  = {0x24, 0x46, 0x67, 0x11, 0x88, 0x43};

and let’s call the radio_whitelist_add() function after esb_init(). We could call the function like this:

radio_whitelist_add(0,m_adv_addr);

 

I have not configured any interrupts to trigger when we get a EVENTS_DEVMATCH. So for checking if we are actually getting the event, we can configure the PPI to toggle a LED each time we get the EVENTS_DEVMATCH.

This can be configured with the following function:

void devmatch_gpiote_toogle( void )
{
	uint32_t PPI_CHANNEL = 0;
    uint32_t PIN_GPIO_LED = 20; // LED 4 on the nRF52832-DK

    // Configure PIN_GPIO as output
    NRF_GPIO->DIRSET = (1UL << PIN_GPIO_LED);
  
    // Configure GPIOTE->TASKS_OUT[0] to toggle PIN_GPIO_LED
    NRF_GPIOTE->CONFIG[0] = (GPIOTE_CONFIG_MODE_Task       << GPIOTE_CONFIG_MODE_Pos) |
                          (GPIOTE_CONFIG_OUTINIT_Low     << GPIOTE_CONFIG_OUTINIT_Pos) |
                          (GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos) |
                          (PIN_GPIO_LED                  << GPIOTE_CONFIG_PSEL_Pos);

    // Configure PPI channel with connection between EVENTS_DEVMATCH and GPIOTE->TASKS_OUT[0]
    NRF_PPI->CH[PPI_CHANNEL].EEP = (uint32_t)&NRF_RADIO->EVENTS_DEVMATCH;
    NRF_PPI->CH[PPI_CHANNEL].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[0];
  
    // Enable PPI channel
    NRF_PPI->CHENSET = (1UL << PPI_CHANNEL);
}

 

We could call the devmatch_gpiote_toogle() function after we have called radio_whitelist_add(). We should also remove the toggling in the nrf_esb_event_handler, i.e. comment out the nrf_gpio_pin_write() functions.

If everthing is working, LED1 should toggle on the transmitter, and LED4 should toggle on the receiver, indicating the we getting the event EVENTS_DEVMATCH.

Here is the main.c files for the transmitter and the receiver for SDK 11, that I used to test this. Note that if this is a new project, I would generally recommend using the latest SDK instead.

main_receiver.c

Fullscreen 8713.main_receiver.c Download

/* Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 *
 */

#include "nrf_esb.h"

#include <stdbool.h>
#include <stdint.h>
#include "sdk_common.h"
#include "nrf.h"
#include "nrf_esb_error_codes.h"
#include "nrf_delay.h"
#include "nrf_gpio.h"
#include "nrf_error.h"
#include "nrf_log.h"
#include "boards.h"
#include "nrf_log.h"


const uint8_t leds_list[LEDS_NUMBER] = LEDS_LIST;
uint8_t led_nr;

nrf_esb_payload_t rx_payload;

void nrf_esb_error_handler(uint32_t err_code, uint32_t line)
{
    NRF_LOG_PRINTF("App failed at line %d with error code: 0x%08x\r\n",
                   line, err_code);
#if DEBUG //lint -e553
    while(true);
#else
    NVIC_SystemReset();
#endif

}

#define APP_ERROR_CHECK(err_code) if(err_code) nrf_esb_error_handler(err_code, __LINE__);

/*lint -save -esym(40, BUTTON_1) -esym(40, BUTTON_2) -esym(40, BUTTON_3) -esym(40, BUTTON_4) -esym(40, LED_1) -esym(40, LED_2) -esym(40, LED_3) -esym(40, LED_4) */

void nrf_esb_event_handler(nrf_esb_evt_t const * p_event)
{
    switch (p_event->evt_id)
    {
        case NRF_ESB_EVENT_TX_SUCCESS:
            NRF_LOG("TX SUCCESS EVENT\r\n");
            break;
        case NRF_ESB_EVENT_TX_FAILED:
            NRF_LOG("TX FAILED EVENT\r\n");
            break;
        case NRF_ESB_EVENT_RX_RECEIVED:
            NRF_LOG("RX RECEIVED EVENT\r\n");
            if (nrf_esb_read_rx_payload(&rx_payload) == NRF_SUCCESS)
            {
                // Set LEDs identical to the ones on the PTX.
                //nrf_gpio_pin_write(LED_1, !(rx_payload.data[1]%8>0 && rx_payload.data[1]%8<=4));
                //nrf_gpio_pin_write(LED_2, !(rx_payload.data[1]%8>1 && rx_payload.data[1]%8<=5));
                //nrf_gpio_pin_write(LED_3, !(rx_payload.data[1]%8>2 && rx_payload.data[1]%8<=6));
                //nrf_gpio_pin_write(LED_4, !(rx_payload.data[1]%8>3));

                NRF_LOG("Receiving packet: ");
                NRF_LOG_HEX_CHAR(rx_payload.data[1]);
                NRF_LOG("\r\n");
            }
            break;
    }
}

void radio_whitelist_add(uint8_t pipe, const uint8_t * addr)
{
  NRF_RADIO->DAP[pipe] = ( (((uint16_t)addr[5]) <<  8)
                          | (((uint16_t)addr[4]))     );

  NRF_RADIO->DAB[pipe] = ( (((uint32_t)addr[3]) << 24)
                          | (((uint32_t)addr[2]) << 16)
                          | (((uint32_t)addr[1]) <<  8)
                          | (((uint32_t)addr[0]))     );

    NRF_RADIO->DACNF |= (1U << (pipe + RADIO_DACNF_TXADD0_Pos));
    NRF_RADIO->DACNF |=  (1U << pipe);
}



void clocks_start( void )
{
    NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
    NRF_CLOCK->TASKS_HFCLKSTART = 1;

    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
}


void gpio_init( void )
{
    LEDS_CONFIGURE(LEDS_MASK);
}


uint32_t esb_init( void )
{
    uint32_t err_code;
    uint8_t base_addr_0[4] = {0xE7, 0xE7, 0xE7, 0xE7};
    uint8_t base_addr_1[4] = {0xC2, 0xC2, 0xC2, 0xC2};
    uint8_t addr_prefix[8] = {0xE7, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8 };
    nrf_esb_config_t nrf_esb_config         = NRF_ESB_DEFAULT_CONFIG;
    nrf_esb_config.payload_length           = 8;
    nrf_esb_config.protocol                 = NRF_ESB_PROTOCOL_ESB_DPL;
    nrf_esb_config.bitrate                  = NRF_ESB_BITRATE_2MBPS;
    nrf_esb_config.mode                     = NRF_ESB_MODE_PRX;
    nrf_esb_config.event_handler            = nrf_esb_event_handler;
    nrf_esb_config.selective_auto_ack       = false;

    err_code = nrf_esb_init(&nrf_esb_config);
    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_base_address_0(base_addr_0);
    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_base_address_1(base_addr_1);
    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_prefixes(addr_prefix, 8);
    VERIFY_SUCCESS(err_code);

    return err_code;
}

void devmatch_gpiote_toogle( void )
{
	uint32_t PPI_CHANNEL = 0;
    uint32_t PIN_GPIO_LED = 20; // LED 4 on the nRF52832-DK

    // Configure PIN_GPIO as output
    NRF_GPIO->DIRSET = (1UL << PIN_GPIO_LED);
  
    // Configure GPIOTE->TASKS_OUT[0] to toggle PIN_GPIO_LED
    NRF_GPIOTE->CONFIG[0] = (GPIOTE_CONFIG_MODE_Task       << GPIOTE_CONFIG_MODE_Pos) |
                          (GPIOTE_CONFIG_OUTINIT_Low     << GPIOTE_CONFIG_OUTINIT_Pos) |
                          (GPIOTE_CONFIG_POLARITY_Toggle << GPIOTE_CONFIG_POLARITY_Pos) |
                          (PIN_GPIO_LED                  << GPIOTE_CONFIG_PSEL_Pos);

    // Configure PPI channel with connection between EVENTS_DEVMATCH and GPIOTE->TASKS_OUT[0]
    NRF_PPI->CH[PPI_CHANNEL].EEP = (uint32_t)&NRF_RADIO->EVENTS_DEVMATCH;
    NRF_PPI->CH[PPI_CHANNEL].TEP = (uint32_t)&NRF_GPIOTE->TASKS_OUT[0];
  
    // Enable PPI channel
    NRF_PPI->CHENSET = (1UL << PPI_CHANNEL);
}


static uint8_t const m_adv_addr[]  = {0x24, 0x46, 0x67, 0x11, 0x88, 0x43};


int main(void)
{
    uint32_t err_code;

    gpio_init();

    err_code = NRF_LOG_INIT();
    APP_ERROR_CHECK(err_code);

    clocks_start();

    err_code = esb_init();
    APP_ERROR_CHECK(err_code);
	radio_whitelist_add(0,m_adv_addr);
	devmatch_gpiote_toogle();

    NRF_LOG("Enhanced ShockBurst Receiver Example running.\r\n");

    err_code = nrf_esb_start_rx();
    APP_ERROR_CHECK(err_code);

    while (true)
    {
        __WFE();
    }
}
/*lint -restore */

main_transmitter.c

Fullscreen 5582.main_transmitter.c Download

/* Copyright (c) 2014 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 *
 */

#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include "sdk_common.h"
#include "nrf.h"
#include "nrf_esb.h"
#include "nrf_error.h"
#include "nrf_esb_error_codes.h"
#include "nrf_delay.h"
#include "nrf_gpio.h"
#include "nrf_log.h"
#include "boards.h"
#include "nrf_delay.h"
#include "nrf_log.h"
#include "app_util.h"



static nrf_esb_payload_t        tx_payload = NRF_ESB_CREATE_PAYLOAD(0, 0x24, 0x46, 0x67, 0x11, 0x88, 0x43);


static nrf_esb_payload_t        rx_payload;

const uint8_t leds_list[LEDS_NUMBER] = LEDS_LIST;

void nrf_esb_error_handler(uint32_t err_code, uint32_t line)
{
    NRF_LOG_PRINTF("App failed at line %d with error code: 0x%08x\r\n",
                   line, err_code);
#if DEBUG //lint -e553
    while(true);
#else
    NVIC_SystemReset();
#endif

}

#define APP_ERROR_CHECK(err_code) if(err_code) nrf_esb_error_handler(err_code, __LINE__);

/*lint -save -esym(40, BUTTON_1) -esym(40, BUTTON_2) -esym(40, BUTTON_3) -esym(40, BUTTON_4) -esym(40, LED_1) -esym(40, LED_2) -esym(40, LED_3) -esym(40, LED_4) */

void nrf_esb_event_handler(nrf_esb_evt_t const * p_event)
{
    switch (p_event->evt_id)
    {
        case NRF_ESB_EVENT_TX_SUCCESS:
            NRF_LOG("TX SUCCESS EVENT\r\n");
            break;
        case NRF_ESB_EVENT_TX_FAILED:
            NRF_LOG("TX FAILED EVENT\r\n");
            (void) nrf_esb_flush_tx();
            (void) nrf_esb_start_tx();
            break;
        case NRF_ESB_EVENT_RX_RECEIVED:
            NRF_LOG("RX RECEIVED EVENT\r\n");
            while (nrf_esb_read_rx_payload(&rx_payload) == NRF_SUCCESS)
            {
                if(rx_payload.length > 0)
                {
                    NRF_LOG("RX RECEIVED PAYLOAD\r\n");
                }
            }
            break;
    }
    NRF_GPIO->OUTCLR = 0xFUL << 12;
    NRF_GPIO->OUTSET = (p_event->tx_attempts & 0x0F) << 12;
}


void clocks_start( void )
{
    NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
    NRF_CLOCK->TASKS_HFCLKSTART = 1;

    while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);
}


void gpio_init( void )
{
    nrf_gpio_range_cfg_output(8, 15);
    LEDS_CONFIGURE(LEDS_MASK);
}


uint32_t esb_init( void )
{
    uint32_t err_code;
    uint8_t base_addr_0[4] = {0xE7, 0xE7, 0xE7, 0xE7};
    uint8_t base_addr_1[4] = {0xC2, 0xC2, 0xC2, 0xC2};
    uint8_t addr_prefix[8] = {0xE7, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8 };

    nrf_esb_config_t nrf_esb_config         = NRF_ESB_DEFAULT_CONFIG;
    nrf_esb_config.protocol                 = NRF_ESB_PROTOCOL_ESB_DPL;
    nrf_esb_config.retransmit_delay         = 600;
    nrf_esb_config.bitrate                  = NRF_ESB_BITRATE_2MBPS;
    nrf_esb_config.event_handler            = nrf_esb_event_handler;
    nrf_esb_config.mode                     = NRF_ESB_MODE_PTX;
    nrf_esb_config.selective_auto_ack       = false;

    err_code = nrf_esb_init(&nrf_esb_config);

    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_base_address_0(base_addr_0);
    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_base_address_1(base_addr_1);
    VERIFY_SUCCESS(err_code);

    err_code = nrf_esb_set_prefixes(addr_prefix, 8);
    VERIFY_SUCCESS(err_code);

    return err_code;
}


int main(void)
{
    ret_code_t err_code;

    gpio_init();

    err_code = NRF_LOG_INIT();
    APP_ERROR_CHECK(err_code);

    clocks_start();

    err_code = esb_init();
    APP_ERROR_CHECK(err_code);

    LEDS_CONFIGURE(LEDS_MASK);

    NRF_LOG("Enhanced ShockBurst Transmitter Example running.\r\n");

    while (true)
    {
        NRF_LOG("Transmitting packet ");
        NRF_LOG_HEX_CHAR(tx_payload.data[1]);
        NRF_LOG("\r\n");

        tx_payload.noack = false;
        if (nrf_esb_write_payload(&tx_payload) == NRF_SUCCESS)
        {
			 nrf_gpio_pin_toggle(LED_1);
        }
        else
        {
            NRF_LOG("Sending packet failed\r\n");
        }

        nrf_delay_us(50000);
    }
}
/*lint -restore */

[fangrui166]

Hi ，

thanks for your example, it is works use pipe 0.

but if change to other pipe ,it is not work.

•  case 1: ok

tx_payload1 = NRF_ESB_CREATE_PAYLOAD(0, 0x24,0x46, 0x67, 0x11, 0x88, 0x43);

radio_whitelist_add(0, addr);

•  case 2: ok

tx_payload1 = NRF_ESB_CREATE_PAYLOAD(0, 0x24,0x46, 0x67, 0x11, 0x88, 0x43);

radio_whitelist_add(1, addr);

• case 3: not work

tx_payload1 = NRF_ESB_CREATE_PAYLOAD(1, 0x24,0x46, 0x67, 0x11, 0x88, 0x43); radio_whitelist_add(1, addr);

could you help me to check why it is not work in other pipe ?

[Sigurd]

Hi,

From the Product Specification we have that "The Device Address match unit assumes that the 48 first bits of the payload is the device address and that bit number 6 in S0 is the TxAdd bit". 

By default, ESB with dynamic payload length does not use or configure the use of S0 in the radio packet. So in order to get consistent results, with all pipes and payload lengths, we need to make some changes in how ESB configures S0 and generates radio packets. I.e. we need to insert the S0 byte before the length of the packet is added. This will require several changes in nrf_esb.c.

I could provide a quick prototype of the changes required. Are you still using SDK 11?

[fangrui166]

Hi ,

thanks for your reply, I have two kinds of develop board pca10028 and pca10040, and now I'm using SDK 14.

NRF_RADIO->PCNF0 = (0 << RADIO_PCNF0_S0LEN_Pos) |
(6 << RADIO_PCNF0_LFLEN_Pos) |
(3 << RADIO_PCNF0_S1LEN_Pos) ;

Change to 

NRF_RADIO->PCNF0 = (0 << RADIO_PCNF0_S0LEN_Pos) |
(8 << RADIO_PCNF0_LFLEN_Pos) |
(3 << RADIO_PCNF0_S1LEN_Pos) ;

It’s ok now.

if this change correct ?

[Sigurd]

Hi,

No, with that you are only increasing the length of the on-air of LENGTH field in number of bits.

Here is a quick prototype of the changes needed (SDK 14.2):

I have hardcoded the S0 byte to be 0x00, and NRF_RADIO->DACNF TXADDx would therefore need to be 0. In the function radio_whitelist_add() , the function should be modified so that it is set to 0 instead of 1. I.e.

NRF_RADIO->DACNF |= (0U << (pipe + RADIO_DACNF_TXADD0_Pos));

Here is the modified nrf_esb.c:

/**
 * Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 * 
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 * 
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 */

#include "nrf_error.h"
#include "nrf_esb.h"
#include "nrf_esb_error_codes.h"
#include "nrf_gpio.h"
#include <string.h>
#include <stddef.h>
#include "sdk_common.h"
#include "sdk_macros.h"
#include "app_util.h"
#include "nrf_log.h"
#include "nrf_delay.h"

#define BIT_MASK_UINT_8(x) (0xFF >> (8 - (x)))
#define NRF_ESB_PIPE_COUNT 8

// Constant parameters
#define RX_WAIT_FOR_ACK_TIMEOUT_US_2MBPS        (48)        /**< 2 Mb RX wait for acknowledgment time-out value. Smallest reliable value - 43. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS        (64)        /**< 1 Mb RX wait for acknowledgment time-out value. Smallest reliable value - 59. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_250KBPS      (250)       /**< 250 Kb RX wait for acknowledgment time-out value. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS_BLE    (73)        /**< 1 Mb RX wait for acknowledgment time-out (combined with BLE). Smallest reliable value - 68.*/

// Interrupt flags
#define     NRF_ESB_INT_TX_SUCCESS_MSK          0x01        /**< Interrupt mask value for TX success. */
#define     NRF_ESB_INT_TX_FAILED_MSK           0x02        /**< Interrupt mask value for TX failure. */
#define     NRF_ESB_INT_RX_DATA_RECEIVED_MSK    0x04        /**< Interrupt mask value for RX_DR. */

#define     NRF_ESB_PID_RESET_VALUE             0xFF        /**< Invalid PID value which is guaranteed to not collide with any valid PID value. */
#define     NRF_ESB_PID_MAX                     3           /**< Maximum value for PID. */
#define     NRF_ESB_CRC_RESET_VALUE             0xFFFF      /**< CRC reset value. */

// Internal Enhanced ShockBurst module state.
typedef enum {
    NRF_ESB_STATE_IDLE,                                     /**< Module idle. */
    NRF_ESB_STATE_PTX_TX,                                   /**< Module transmitting without acknowledgment. */
    NRF_ESB_STATE_PTX_TX_ACK,                               /**< Module transmitting with acknowledgment. */
    NRF_ESB_STATE_PTX_RX_ACK,                               /**< Module transmitting with acknowledgment and reception of payload with the acknowledgment response. */
    NRF_ESB_STATE_PRX,                                      /**< Module receiving packets without acknowledgment. */
    NRF_ESB_STATE_PRX_SEND_ACK,                             /**< Module transmitting acknowledgment in RX mode. */
} nrf_esb_mainstate_t;


#define DISABLE_RF_IRQ()      NVIC_DisableIRQ(RADIO_IRQn)
#define ENABLE_RF_IRQ()       NVIC_EnableIRQ(RADIO_IRQn)

#define _RADIO_SHORTS_COMMON ( RADIO_SHORTS_READY_START_Msk | RADIO_SHORTS_END_DISABLE_Msk | \
            RADIO_SHORTS_ADDRESS_RSSISTART_Msk | RADIO_SHORTS_DISABLED_RSSISTOP_Msk )

#define VERIFY_PAYLOAD_LENGTH(p)                            \
do                                                          \
{                                                           \
    if (p->length == 0 ||                                    \
       p->length > NRF_ESB_MAX_PAYLOAD_LENGTH ||            \
       (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB &&  \
        p->length > m_config_local.payload_length))         \
    {                                                       \
        return NRF_ERROR_INVALID_LENGTH;                    \
    }                                                       \
}while (0)


/* @brief Structure holding pipe info PID and CRC and acknowledgment payload. */
typedef struct
{
    uint16_t    crc;                                      /**< CRC value of the last received packet (Used to detect retransmits). */
    uint8_t     pid;                                      /**< Packet ID of the last received packet (Used to detect retransmits). */
    bool        ack_payload;                              /**< Flag indicating the state of the transmission of acknowledgment payloads. */
	uint8_t     s0;
} pipe_info_t;


/* @brief  First-in, first-out queue of payloads to be transmitted. */
typedef struct
{
    nrf_esb_payload_t * p_payload[NRF_ESB_TX_FIFO_SIZE];  /**< Pointer to the actual queue. */
    uint32_t            entry_point;                      /**< Current start of queue. */
    uint32_t            exit_point;                       /**< Current end of queue. */
    uint32_t            count;                            /**< Current number of elements in the queue. */
} nrf_esb_payload_tx_fifo_t;


/* @brief First-in, first-out queue of received payloads. */
typedef struct
{
    nrf_esb_payload_t * p_payload[NRF_ESB_RX_FIFO_SIZE];  /**< Pointer to the actual queue. */
    uint32_t            entry_point;                      /**< Current start of queue. */
    uint32_t            exit_point;                       /**< Current end of queue. */
    uint32_t            count;                            /**< Current number of elements in the queue. */
} nrf_esb_payload_rx_fifo_t;


/**@brief Enhanced ShockBurst address.
 *
 * Enhanced ShockBurst addresses consist of a base address and a prefix
 *          that is unique for each pipe. See @ref esb_addressing in the ESB user
 *          guide for more information.
*/
typedef struct
{
    uint8_t base_addr_p0[4];        /**< Base address for pipe 0 encoded in big endian. */
    uint8_t base_addr_p1[4];        /**< Base address for pipe 1-7 encoded in big endian. */
    uint8_t pipe_prefixes[8];       /**< Address prefix for pipe 0 to 7. */
    uint8_t num_pipes;              /**< Number of pipes available. */
    uint8_t addr_length;            /**< Length of the address including the prefix. */
    uint8_t rx_pipes_enabled;       /**< Bitfield for enabled pipes. */
    uint8_t rf_channel;             /**< Channel to use (must be between 0 and 100). */
} nrf_esb_address_t;


// Module state
static bool                         m_esb_initialized           = false;
static nrf_esb_mainstate_t          m_nrf_esb_mainstate         = NRF_ESB_STATE_IDLE;
static nrf_esb_payload_t          * mp_current_payload;

static nrf_esb_event_handler_t      m_event_handler;

// Address parameters
__ALIGN(4) static nrf_esb_address_t m_esb_addr = NRF_ESB_ADDR_DEFAULT;

// RF parameters
static nrf_esb_config_t             m_config_local;

// TX FIFO
static nrf_esb_payload_t            m_tx_fifo_payload[NRF_ESB_TX_FIFO_SIZE];
static nrf_esb_payload_tx_fifo_t    m_tx_fifo;

// RX FIFO
static nrf_esb_payload_t            m_rx_fifo_payload[NRF_ESB_RX_FIFO_SIZE];
static nrf_esb_payload_rx_fifo_t    m_rx_fifo;

// Payload buffers
static  uint8_t                     m_tx_payload_buffer[NRF_ESB_MAX_PAYLOAD_LENGTH + 3]; //Added 1 for S0
static  uint8_t                     m_rx_payload_buffer[NRF_ESB_MAX_PAYLOAD_LENGTH + 3]; //Added 1 for S0

// Run time variables
static volatile uint32_t            m_interrupt_flags = 0;
static uint8_t                      m_pids[NRF_ESB_PIPE_COUNT];
static pipe_info_t                  m_rx_pipe_info[NRF_ESB_PIPE_COUNT];
static volatile uint32_t            m_retransmits_remaining;
static volatile uint32_t            m_last_tx_attempts;
static volatile uint32_t            m_wait_for_ack_timeout_us;

// nRF52 address workaround enable
#ifdef NRF52
static bool                         m_address_hang_fix_enable = true;
#endif
static uint32_t                     m_radio_shorts_common = _RADIO_SHORTS_COMMON;

// These function pointers are changed dynamically, depending on protocol configuration and state.
static void (*on_radio_disabled)(void) = 0;
static void (*on_radio_end)(void) = 0;
static void (*update_rf_payload_format)(uint32_t payload_length) = 0;


// The following functions are assigned to the function pointers above.
static void on_radio_disabled_tx_noack(void);
static void on_radio_disabled_tx(void);
static void on_radio_disabled_tx_wait_for_ack(void);
static void on_radio_disabled_rx(void);
static void on_radio_disabled_rx_ack(void);


#define NRF_ESB_ADDR_UPDATE_MASK_BASE0          (1 << 0)    /*< Mask value to signal updating BASE0 radio address. */
#define NRF_ESB_ADDR_UPDATE_MASK_BASE1          (1 << 1)    /*< Mask value to signal updating BASE1 radio address. */
#define NRF_ESB_ADDR_UPDATE_MASK_PREFIX         (1 << 2)    /*< Mask value to signal updating radio prefixes. */


// Function to do bytewise bit-swap on an unsigned 32-bit value
static uint32_t bytewise_bit_swap(uint8_t const * p_inp)
{
    uint32_t inp = (*(uint32_t*)p_inp);
#if __CORTEX_M == (0x04U)
    return __REV((uint32_t)__RBIT(inp)); //lint -esym(628, __rev) -esym(526, __rev) -esym(628, __rbit) -esym(526, __rbit) */
#else
    inp = (inp & 0xF0F0F0F0) >> 4 | (inp & 0x0F0F0F0F) << 4;
    inp = (inp & 0xCCCCCCCC) >> 2 | (inp & 0x33333333) << 2;
    inp = (inp & 0xAAAAAAAA) >> 1 | (inp & 0x55555555) << 1;
    return inp;
#endif
}


// Internal function to convert base addresses from nRF24L type addressing to nRF51 type addressing
static uint32_t addr_conv(uint8_t const* p_addr)
{
    return __REV(bytewise_bit_swap(p_addr)); //lint -esym(628, __rev) -esym(526, __rev) */
}


static ret_code_t apply_address_workarounds()
{
#ifdef NRF52
    //  Set up radio parameters.
    NRF_RADIO->MODECNF0 = (NRF_RADIO->MODECNF0 & ~RADIO_MODECNF0_RU_Msk) | RADIO_MODECNF0_RU_Default << RADIO_MODECNF0_RU_Pos;

    // Workaround for nRF52832 Rev 1 Errata 102 and nRF52832 Rev 1 Errata 106. This will reduce sensitivity by 3dB.
    *((volatile uint32_t *)0x40001774) = (*((volatile uint32_t *)0x40001774) & 0xFFFFFFFE) | 0x01000000;
#endif
    return NRF_SUCCESS;
}


static void update_rf_payload_format_esb_dpl(uint32_t payload_length)
{
#if (NRF_ESB_MAX_PAYLOAD_LENGTH <= 32)
    // Using 6 bits for length
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |  //Setting 1 for S0 byte
                       (6 << RADIO_PCNF0_LFLEN_Pos) |
                       (3 << RADIO_PCNF0_S1LEN_Pos) ;
#else
    // Using 8 bits for length
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |  //Setting 1 for S0 byte
                       (8 << RADIO_PCNF0_LFLEN_Pos) |
                       (3 << RADIO_PCNF0_S1LEN_Pos) ;
#endif
    NRF_RADIO->PCNF1 = (RADIO_PCNF1_WHITEEN_Disabled    << RADIO_PCNF1_WHITEEN_Pos) |
                       (RADIO_PCNF1_ENDIAN_Little          << RADIO_PCNF1_ENDIAN_Pos)  |
                       ((m_esb_addr.addr_length - 1)    << RADIO_PCNF1_BALEN_Pos)   |
                       (0                               << RADIO_PCNF1_STATLEN_Pos) |
                       (NRF_ESB_MAX_PAYLOAD_LENGTH      << RADIO_PCNF1_MAXLEN_Pos);
}


static void update_rf_payload_format_esb(uint32_t payload_length)
{
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |
                       (0 << RADIO_PCNF0_LFLEN_Pos) |
                       (1 << RADIO_PCNF0_S1LEN_Pos);

    NRF_RADIO->PCNF1 = (RADIO_PCNF1_WHITEEN_Disabled    << RADIO_PCNF1_WHITEEN_Pos) |
                       (RADIO_PCNF1_ENDIAN_Little          << RADIO_PCNF1_ENDIAN_Pos)  |
                       ((m_esb_addr.addr_length - 1)    << RADIO_PCNF1_BALEN_Pos)   |
                       (payload_length                  << RADIO_PCNF1_STATLEN_Pos) |
                       (payload_length                  << RADIO_PCNF1_MAXLEN_Pos);
}


static void update_radio_addresses(uint8_t update_mask)
{
    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_BASE0) != 0)
    {
        NRF_RADIO->BASE0 = addr_conv(m_esb_addr.base_addr_p0);
    }

    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_BASE1) != 0)
    {
        NRF_RADIO->BASE1 = addr_conv(m_esb_addr.base_addr_p1);
    }

    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_PREFIX) != 0)
    {
        NRF_RADIO->PREFIX0 = bytewise_bit_swap(&m_esb_addr.pipe_prefixes[0]);
        NRF_RADIO->PREFIX1 = bytewise_bit_swap(&m_esb_addr.pipe_prefixes[4]);
    }
}


static void update_radio_tx_power()
{
    NRF_RADIO->TXPOWER = m_config_local.tx_output_power << RADIO_TXPOWER_TXPOWER_Pos;
}


static bool update_radio_bitrate()
{
    NRF_RADIO->MODE = m_config_local.bitrate << RADIO_MODE_MODE_Pos;

    switch (m_config_local.bitrate)
    {
        case NRF_ESB_BITRATE_2MBPS:
#ifdef NRF52
        case NRF_ESB_BITRATE_2MBPS_BLE:
#endif
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_2MBPS;
            break;

        case NRF_ESB_BITRATE_1MBPS:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS;
            break;

#ifdef NRF51
        case NRF_ESB_BITRATE_250KBPS:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_250KBPS;
            break;
#endif
        
        case NRF_ESB_BITRATE_1MBPS_BLE:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS_BLE;
            break;

        default:
            // Should not be reached
            return false;
    }
    return true;
}


static bool update_radio_protocol()
{
    switch (m_config_local.protocol)
    {
        case NRF_ESB_PROTOCOL_ESB_DPL:
            update_rf_payload_format = update_rf_payload_format_esb_dpl;
            break;

        case NRF_ESB_PROTOCOL_ESB:
            update_rf_payload_format = update_rf_payload_format_esb;
            break;

        default:
            // Should not be reached
            return false;
    }
    return true;
}


static bool update_radio_crc()
{
    switch(m_config_local.crc)
    {
        case NRF_ESB_CRC_16BIT:
            NRF_RADIO->CRCINIT = 0xFFFFUL;      // Initial value
            NRF_RADIO->CRCPOLY = 0x11021UL;     // CRC poly: x^16+x^12^x^5+1
            break;
        
        case NRF_ESB_CRC_8BIT:
            NRF_RADIO->CRCINIT = 0xFFUL;        // Initial value
            NRF_RADIO->CRCPOLY = 0x107UL;       // CRC poly: x^8+x^2^x^1+1
            break;
        
        case NRF_ESB_CRC_OFF:
            break;
        
        default:
            return false;
    }
    NRF_RADIO->CRCCNF = m_config_local.crc << RADIO_CRCCNF_LEN_Pos;
    return true;
}


static bool update_radio_parameters()
{
    bool params_valid = true;
    update_radio_tx_power();
    params_valid &= update_radio_bitrate();
    params_valid &= update_radio_protocol();
    params_valid &= update_radio_crc();
    update_rf_payload_format(m_config_local.payload_length);
    params_valid &= (m_config_local.retransmit_delay >= NRF_ESB_RETRANSMIT_DELAY_MIN);
    return params_valid;
}


static void reset_fifos()
{
    m_tx_fifo.entry_point = 0;
    m_tx_fifo.exit_point  = 0;
    m_tx_fifo.count       = 0;

    m_rx_fifo.entry_point = 0;
    m_rx_fifo.exit_point  = 0;
    m_rx_fifo.count       = 0;
}


static void initialize_fifos()
{
    reset_fifos();

    for (int i = 0; i < NRF_ESB_TX_FIFO_SIZE; i++)
    {
        m_tx_fifo.p_payload[i] = &m_tx_fifo_payload[i];
    }

    for (int i = 0; i < NRF_ESB_RX_FIFO_SIZE; i++)
    {
        m_rx_fifo.p_payload[i] = &m_rx_fifo_payload[i];
    }
}


static void tx_fifo_remove_last()
{
    if (m_tx_fifo.count > 0)
    {
        DISABLE_RF_IRQ();

        m_tx_fifo.count--;
        if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
        {
            m_tx_fifo.exit_point = 0;
        }

        ENABLE_RF_IRQ();
    }
}

/** @brief  Function to push the content of the rx_buffer to the RX FIFO.
 *
 *  The module will point the register NRF_RADIO->PACKETPTR to a buffer for receiving packets.
 *  After receiving a packet the module will call this function to copy the received data to
 *  the RX FIFO.
 *
 *  @param  pipe Pipe number to set for the packet.
 *  @param  pid  Packet ID.
 *
 *  @retval true   Operation successful.
 *  @retval false  Operation failed.
 */
static bool rx_fifo_push_rfbuf(uint8_t pipe, uint8_t pid)
{
    if (m_rx_fifo.count < NRF_ESB_RX_FIFO_SIZE)
    {
        if (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB_DPL)
        {
            if (m_rx_payload_buffer[1] > NRF_ESB_MAX_PAYLOAD_LENGTH) //Moved 1 byte. Changed from 0 to 1.
            {
                return false;
            }

            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = m_rx_payload_buffer[1]; //Length is moved 1 byte because of S0. Changed from 0 to 1
        }
        else if (m_config_local.mode == NRF_ESB_MODE_PTX)
        {
            // Received packet is an acknowledgment
            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = 0;
        }
        else
        {
            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = m_config_local.payload_length;
        }

        memcpy(m_rx_fifo.p_payload[m_rx_fifo.entry_point]->data, &m_rx_payload_buffer[3], //Moved 1 byte. Changed from 2 to 3.
               m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length);

        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->pipe  = pipe;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->rssi  = NRF_RADIO->RSSISAMPLE;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->pid   = pid;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->noack = !(m_rx_payload_buffer[2] & 0x01);  //moved 1 byte. Changed from 1 to 2.
        if (++m_rx_fifo.entry_point >= NRF_ESB_RX_FIFO_SIZE)
        {
            m_rx_fifo.entry_point = 0;
        }
        m_rx_fifo.count++;

        return true;
    }

    return false;
}


static void sys_timer_init()
{
    // Configure the system timer with a 1 MHz base frequency
    NRF_ESB_SYS_TIMER->PRESCALER = 4;
    NRF_ESB_SYS_TIMER->BITMODE   = TIMER_BITMODE_BITMODE_16Bit;
    NRF_ESB_SYS_TIMER->SHORTS    = TIMER_SHORTS_COMPARE1_CLEAR_Msk | TIMER_SHORTS_COMPARE1_STOP_Msk;
}


static void ppi_init()
{
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_START].EEP = (uint32_t)&NRF_RADIO->EVENTS_READY;
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_START].TEP = (uint32_t)&NRF_ESB_SYS_TIMER->TASKS_START;

    NRF_PPI->CH[NRF_ESB_PPI_TIMER_STOP].EEP  = (uint32_t)&NRF_RADIO->EVENTS_ADDRESS;
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_STOP].TEP  = (uint32_t)&NRF_ESB_SYS_TIMER->TASKS_STOP;

    NRF_PPI->CH[NRF_ESB_PPI_RX_TIMEOUT].EEP  = (uint32_t)&NRF_ESB_SYS_TIMER->EVENTS_COMPARE[0];
    NRF_PPI->CH[NRF_ESB_PPI_RX_TIMEOUT].TEP  = (uint32_t)&NRF_RADIO->TASKS_DISABLE;

    NRF_PPI->CH[NRF_ESB_PPI_TX_START].EEP    = (uint32_t)&NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1];
    NRF_PPI->CH[NRF_ESB_PPI_TX_START].TEP    = (uint32_t)&NRF_RADIO->TASKS_TXEN;
}


static void start_tx_transaction()
{
    bool ack;

    m_last_tx_attempts = 1;
    // Prepare the payload
    mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];


    switch (m_config_local.protocol)
    {
        case NRF_ESB_PROTOCOL_ESB: //We are using ESB_DPL. No changes done here.
            update_rf_payload_format(mp_current_payload->length);
            m_tx_payload_buffer[0] = mp_current_payload->pid;
            m_tx_payload_buffer[1] = 0;
            memcpy(&m_tx_payload_buffer[2], mp_current_payload->data, mp_current_payload->length);

            NRF_RADIO->SHORTS   = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
            NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk | RADIO_INTENSET_READY_Msk;

            // Configure the retransmit counter
            m_retransmits_remaining = m_config_local.retransmit_count;
            on_radio_disabled = on_radio_disabled_tx;
            m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            break;

        case NRF_ESB_PROTOCOL_ESB_DPL:
            ack = !mp_current_payload->noack || !m_config_local.selective_auto_ack;
			m_tx_payload_buffer[0] = 0x00; //setting s0 as first byte in packet. Hardcoded to 0x00 for now
            m_tx_payload_buffer[1] = mp_current_payload->length; //Length has been moved 1 byte. Changed from 0 to 1.
            m_tx_payload_buffer[2] = mp_current_payload->pid << 1;  //Moved 1 byte. Changed from 1 to 2.
            m_tx_payload_buffer[2] |= mp_current_payload->noack ? 0x00 : 0x01; //Moved 1 byte. Changed from 1 to 2.
            memcpy(&m_tx_payload_buffer[3], mp_current_payload->data, mp_current_payload->length); //Moved 1 byte. Changed from 2 to 3.

            // Handling ack if noack is set to false or if selective auto ack is turned off
            if (ack)
            {
                NRF_RADIO->SHORTS   = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
                NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk | RADIO_INTENSET_READY_Msk;

                // Configure the retransmit counter
                m_retransmits_remaining = m_config_local.retransmit_count;
                on_radio_disabled = on_radio_disabled_tx;
                m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            }
            else
            {
                NRF_RADIO->SHORTS   = m_radio_shorts_common;
                NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk;
                on_radio_disabled   = on_radio_disabled_tx_noack;
                m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX;
            }
            break;

        default:
            // Should not be reached
            break;
    }

    NRF_RADIO->TXADDRESS    = mp_current_payload->pipe;
    NRF_RADIO->RXADDRESSES  = 1 << mp_current_payload->pipe;

    NRF_RADIO->FREQUENCY    = m_esb_addr.rf_channel;
    NRF_RADIO->PACKETPTR    = (uint32_t)m_tx_payload_buffer;

    NVIC_ClearPendingIRQ(RADIO_IRQn);
    NVIC_EnableIRQ(RADIO_IRQn);

    NRF_RADIO->EVENTS_ADDRESS = 0;
    NRF_RADIO->EVENTS_PAYLOAD = 0;
    NRF_RADIO->EVENTS_DISABLED = 0;

    DEBUG_PIN_SET(DEBUGPIN4);
    NRF_RADIO->TASKS_TXEN  = 1;
}


static void on_radio_disabled_tx_noack()
{
    m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
    tx_fifo_remove_last();

    if (m_tx_fifo.count == 0)
    {
        m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
        NVIC_SetPendingIRQ(ESB_EVT_IRQ);
    }
    else
    {
        NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        start_tx_transaction();
    }
}


static void on_radio_disabled_tx()
{
    // Remove the DISABLED -> RXEN shortcut, to make sure the radio stays
    // disabled after the RX window
    NRF_RADIO->SHORTS           = m_radio_shorts_common;

    // Make sure the timer is started the next time the radio is ready,
    // and that it will disable the radio automatically if no packet is
    // received by the time defined in m_wait_for_ack_timeout_us
    NRF_ESB_SYS_TIMER->CC[0]    = m_wait_for_ack_timeout_us;
    NRF_ESB_SYS_TIMER->CC[1]    = m_config_local.retransmit_delay - 130;
    NRF_ESB_SYS_TIMER->TASKS_CLEAR = 1;
    NRF_ESB_SYS_TIMER->EVENTS_COMPARE[0] = 0;
    NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1] = 0;

    NRF_PPI->CHENSET            = (1 << NRF_ESB_PPI_TIMER_START) |
                                  (1 << NRF_ESB_PPI_RX_TIMEOUT) |
                                  (1 << NRF_ESB_PPI_TIMER_STOP);
    NRF_PPI->CHENCLR            = (1 << NRF_ESB_PPI_TX_START);
    NRF_RADIO->EVENTS_END       = 0;

    if (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB)
    {
        update_rf_payload_format(0);
    }

    NRF_RADIO->PACKETPTR        = (uint32_t)m_rx_payload_buffer;
    on_radio_disabled           = on_radio_disabled_tx_wait_for_ack;
    m_nrf_esb_mainstate         = NRF_ESB_STATE_PTX_RX_ACK;
}


static void on_radio_disabled_tx_wait_for_ack()
{
    // This marks the completion of a TX_RX sequence (TX with ACK)

    // Make sure the timer will not deactivate the radio if a packet is received
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TIMER_STOP);

    // If the radio has received a packet and the CRC status is OK
    if (NRF_RADIO->EVENTS_END && NRF_RADIO->CRCSTATUS != 0)
    {
        NRF_ESB_SYS_TIMER->TASKS_STOP = 1;
        NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TX_START);
        m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
        m_last_tx_attempts = m_config_local.retransmit_count - m_retransmits_remaining + 1;

        tx_fifo_remove_last();

        if (m_config_local.protocol != NRF_ESB_PROTOCOL_ESB && m_rx_payload_buffer[0] > 0)
        {
            if (rx_fifo_push_rfbuf((uint8_t)NRF_RADIO->TXADDRESS, m_rx_payload_buffer[1] >> 1))
            {
                m_interrupt_flags |= NRF_ESB_INT_RX_DATA_RECEIVED_MSK;
            }
        }

        if ((m_tx_fifo.count == 0) || (m_config_local.tx_mode == NRF_ESB_TXMODE_MANUAL))
        {
            m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
        else
        {
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
            start_tx_transaction();
        }
    }
    else
    {
        if (m_retransmits_remaining-- == 0)
        {
            NRF_ESB_SYS_TIMER->TASKS_STOP = 1;
            NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TX_START);
            // All retransmits are expended, and the TX operation is suspended
            m_last_tx_attempts = m_config_local.retransmit_count + 1;
            m_interrupt_flags |= NRF_ESB_INT_TX_FAILED_MSK;

            m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
        else
        {
            // There are still more retransmits left, TX mode should be
            // entered again as soon as the system timer reaches CC[1].
            NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
            update_rf_payload_format(mp_current_payload->length);
            NRF_RADIO->PACKETPTR = (uint32_t)m_tx_payload_buffer;
            on_radio_disabled = on_radio_disabled_tx;
            m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            NRF_ESB_SYS_TIMER->TASKS_START = 1;
            NRF_PPI->CHENSET = (1 << NRF_ESB_PPI_TX_START);
            if (NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1])
            {
                NRF_RADIO->TASKS_TXEN = 1;
            }
        }
    }
}

static void clear_events_restart_rx(void)
{
    NRF_RADIO->SHORTS = m_radio_shorts_common;
    update_rf_payload_format(m_config_local.payload_length);
    NRF_RADIO->PACKETPTR = (uint32_t)m_rx_payload_buffer;
    NRF_RADIO->EVENTS_DISABLED = 0;
    NRF_RADIO->TASKS_DISABLE = 1;

    while (NRF_RADIO->EVENTS_DISABLED == 0);

    NRF_RADIO->EVENTS_DISABLED = 0;
    NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;

    NRF_RADIO->TASKS_RXEN = 1;
}

static void on_radio_disabled_rx(void)
{
    bool            ack                = false;
    bool            retransmit_payload = false;
    bool            send_rx_event      = true;
    pipe_info_t *   p_pipe_info;

    if (NRF_RADIO->CRCSTATUS == 0)
    {
        clear_events_restart_rx();
        return;
    }

    if (m_rx_fifo.count >= NRF_ESB_RX_FIFO_SIZE)
    {
        clear_events_restart_rx();
        return;
    }

    p_pipe_info = &m_rx_pipe_info[NRF_RADIO->RXMATCH];
    if (NRF_RADIO->RXCRC             == p_pipe_info->crc &&
        (m_rx_payload_buffer[2] >> 1) == p_pipe_info->pid   //Moved 1 byte. Changed from 1 to 2.
       )
    {
        retransmit_payload = true;
        send_rx_event = false;
    }

    p_pipe_info->pid = m_rx_payload_buffer[2] >> 1;  //Moved 1 byte. Changed from 1 to 2.
    p_pipe_info->crc = NRF_RADIO->RXCRC;

    if ((m_config_local.selective_auto_ack == false) || ((m_rx_payload_buffer[2] & 0x01) == 1)) //Moved 1 byte. Changed from 1 to 2.
    {
        ack = true;
    }

    if (ack)
    {
        NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;

        switch (m_config_local.protocol)
        {
            case NRF_ESB_PROTOCOL_ESB_DPL:
                {
                    if (m_tx_fifo.count > 0 &&
                        (m_tx_fifo.p_payload[m_tx_fifo.exit_point]->pipe == NRF_RADIO->RXMATCH)
                       )
                    {
                        // Pipe stays in ACK with payload until TX FIFO is empty
                        // Do not report TX success on first ack payload or retransmit
                        if (p_pipe_info->ack_payload == true && !retransmit_payload)
                        {
                            if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
                            {
                                m_tx_fifo.exit_point = 0;
                            }

                            m_tx_fifo.count--;

                            // ACK payloads also require TX_DS
                            // (page 40 of the 'nRF24LE1_Product_Specification_rev1_6.pdf').
                            m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
                        }

                        p_pipe_info->ack_payload = true;

                        mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];

                        update_rf_payload_format(mp_current_payload->length);
						m_tx_payload_buffer[0] = 0x00; // Hardcoded S0 to 0x00.
                        m_tx_payload_buffer[1] = mp_current_payload->length;   //Moved 1 byte. Changed from 0 to 1.
                        memcpy(&m_tx_payload_buffer[3],   //Moved 1 byte. Changed from 2 to 3.
                               mp_current_payload->data,
                               mp_current_payload->length);
                    }
                    else
                    {
                        p_pipe_info->ack_payload = false;
                        update_rf_payload_format(0);
						m_tx_payload_buffer[0] = 0x00; // Hardcoded S0 to 0x00.
                        m_tx_payload_buffer[1] = 0; //Moved 1 byte. Changed from 0 to 1.
                    }

                    m_tx_payload_buffer[2] = m_rx_payload_buffer[2]; //Moved 1 byte. Changed from 1 to 2.
                }
                break;

            case NRF_ESB_PROTOCOL_ESB: //Using DPL. No changes
                {
                    update_rf_payload_format(0);
                    m_tx_payload_buffer[0] = m_rx_payload_buffer[0];
                    m_tx_payload_buffer[1] = 0;
                }
                break;
        }

        m_nrf_esb_mainstate = NRF_ESB_STATE_PRX_SEND_ACK;
        NRF_RADIO->TXADDRESS = NRF_RADIO->RXMATCH;
        NRF_RADIO->PACKETPTR = (uint32_t)m_tx_payload_buffer;
        on_radio_disabled = on_radio_disabled_rx_ack;
    }
    else
    {
        clear_events_restart_rx();
    }

    if (send_rx_event)
    {
        // Push the new packet to the RX buffer and trigger a received event if the operation was
        // successful.
        if (rx_fifo_push_rfbuf(NRF_RADIO->RXMATCH, p_pipe_info->pid))
        {
            m_interrupt_flags |= NRF_ESB_INT_RX_DATA_RECEIVED_MSK;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
    }
}


static void on_radio_disabled_rx_ack(void)
{
    NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;
    update_rf_payload_format(m_config_local.payload_length);

    NRF_RADIO->PACKETPTR = (uint32_t)m_rx_payload_buffer;
    on_radio_disabled = on_radio_disabled_rx;

    m_nrf_esb_mainstate = NRF_ESB_STATE_PRX;
}


/**@brief Function for clearing pending interrupts.
 *
 * @param[in,out]   p_interrupts        Pointer to the value that holds the current interrupts.
 *
 * @retval  NRF_SUCCESS                     If the interrupts were cleared successfully.
 * @retval  NRF_ERROR_NULL                  If the required parameter was NULL.
 * @retval  NRF_INVALID_STATE               If the module is not initialized.
 */
static uint32_t nrf_esb_get_clear_interrupts(uint32_t * p_interrupts)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_interrupts);

    DISABLE_RF_IRQ();

    *p_interrupts = m_interrupt_flags;
    m_interrupt_flags = 0;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


void RADIO_IRQHandler()
{
    if (NRF_RADIO->EVENTS_READY && (NRF_RADIO->INTENSET & RADIO_INTENSET_READY_Msk))
    {
        NRF_RADIO->EVENTS_READY = 0;
        DEBUG_PIN_SET(DEBUGPIN1);
    }

    if (NRF_RADIO->EVENTS_END && (NRF_RADIO->INTENSET & RADIO_INTENSET_END_Msk))
    {
        NRF_RADIO->EVENTS_END = 0;
        DEBUG_PIN_SET(DEBUGPIN2);

        // Call the correct on_radio_end function, depending on the current protocol state
        if (on_radio_end)
        {
            on_radio_end();
        }
    }

    if (NRF_RADIO->EVENTS_DISABLED && (NRF_RADIO->INTENSET & RADIO_INTENSET_DISABLED_Msk))
    {
        NRF_RADIO->EVENTS_DISABLED = 0;
        DEBUG_PIN_SET(DEBUGPIN3);

        // Call the correct on_radio_disable function, depending on the current protocol state
        if (on_radio_disabled)
        {
            on_radio_disabled();
        }
    }

    DEBUG_PIN_CLR(DEBUGPIN1);
    DEBUG_PIN_CLR(DEBUGPIN2);
    DEBUG_PIN_CLR(DEBUGPIN3);
    DEBUG_PIN_CLR(DEBUGPIN4);
}


uint32_t nrf_esb_init(nrf_esb_config_t const * p_config)
{
    uint32_t err_code;

    VERIFY_PARAM_NOT_NULL(p_config);

    if (m_esb_initialized)
    {
        err_code = nrf_esb_disable();
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    }

    m_event_handler = p_config->event_handler;

    memcpy(&m_config_local, p_config, sizeof(nrf_esb_config_t));
    
    m_interrupt_flags    = 0;

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));
    memset(m_pids, 0, sizeof(m_pids));

    VERIFY_TRUE(update_radio_parameters(), NRF_ERROR_INVALID_PARAM);

    // Configure radio address registers according to ESB default values
    NRF_RADIO->BASE0   = 0xE7E7E7E7;
    NRF_RADIO->BASE1   = 0x43434343;
    NRF_RADIO->PREFIX0 = 0x23C343E7;
    NRF_RADIO->PREFIX1 = 0x13E363A3;
    
    initialize_fifos();

    sys_timer_init();

    ppi_init();

    NVIC_SetPriority(RADIO_IRQn, m_config_local.radio_irq_priority & ESB_IRQ_PRIORITY_MSK);
    NVIC_SetPriority(ESB_EVT_IRQ, m_config_local.event_irq_priority & ESB_IRQ_PRIORITY_MSK);
    NVIC_EnableIRQ(ESB_EVT_IRQ);

#ifdef NRF52
    if(m_address_hang_fix_enable)
    {
        // Setup a timeout timer to start on an ADDRESS match, and stop on a BCMATCH event.
        // If the BCMATCH event never occurs the CC[0] event will fire, and the timer interrupt will disable the radio to recover.
        m_radio_shorts_common |= RADIO_SHORTS_ADDRESS_BCSTART_Msk;
        NRF_RADIO->BCC = 2;
        NRF_ESB_BUGFIX_TIMER->BITMODE = TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos;
        NRF_ESB_BUGFIX_TIMER->PRESCALER = 4;
        NRF_ESB_BUGFIX_TIMER->CC[0] = 5;
        NRF_ESB_BUGFIX_TIMER->SHORTS = TIMER_SHORTS_COMPARE0_STOP_Msk | TIMER_SHORTS_COMPARE0_CLEAR_Msk;
        NRF_ESB_BUGFIX_TIMER->MODE = TIMER_MODE_MODE_Timer << TIMER_MODE_MODE_Pos;
        NRF_ESB_BUGFIX_TIMER->INTENSET = TIMER_INTENSET_COMPARE0_Msk;
        NRF_ESB_BUGFIX_TIMER->TASKS_CLEAR = 1;
        NVIC_SetPriority(NRF_ESB_BUGFIX_TIMER_IRQn, 5);
        NVIC_EnableIRQ(NRF_ESB_BUGFIX_TIMER_IRQn);

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX1].EEP = (uint32_t)&NRF_RADIO->EVENTS_ADDRESS;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX1].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_START;

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX2].EEP = (uint32_t)&NRF_RADIO->EVENTS_BCMATCH;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX2].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_STOP;

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX3].EEP = (uint32_t)&NRF_RADIO->EVENTS_BCMATCH;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX3].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_CLEAR;

        NRF_PPI->CHENSET = (1 << NRF_ESB_PPI_BUGFIX1) | (1 << NRF_ESB_PPI_BUGFIX2) | (1 << NRF_ESB_PPI_BUGFIX3);
    }
#endif

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
    m_esb_initialized = true;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_suspend(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    // Clear PPI
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_TIMER_STOP)  |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TX_START);

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_disable(void)
{
    // Clear PPI
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_TIMER_STOP)  |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TX_START);

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

    reset_fifos();

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));
    memset(m_pids, 0, sizeof(m_pids));

    // Disable the radio
    NVIC_DisableIRQ(ESB_EVT_IRQ);
    NRF_RADIO->SHORTS = RADIO_SHORTS_READY_START_Enabled << RADIO_SHORTS_READY_START_Pos |
                        RADIO_SHORTS_END_DISABLE_Enabled << RADIO_SHORTS_END_DISABLE_Pos;

    return NRF_SUCCESS;
}


bool nrf_esb_is_idle(void)
{
    return m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE;
}


void ESB_EVT_IRQHandler(void)
{
    ret_code_t      err_code;
    uint32_t        interrupts;
    nrf_esb_evt_t   event;

    event.tx_attempts = m_last_tx_attempts;

    err_code = nrf_esb_get_clear_interrupts(&interrupts);
    if (err_code == NRF_SUCCESS && m_event_handler != 0)
    {
        if (interrupts & NRF_ESB_INT_TX_SUCCESS_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_TX_SUCCESS;
            m_event_handler(&event);
        }
        if (interrupts & NRF_ESB_INT_TX_FAILED_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_TX_FAILED;
            m_event_handler(&event);
        }
        if (interrupts & NRF_ESB_INT_RX_DATA_RECEIVED_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_RX_RECEIVED;
            m_event_handler(&event);
        }
    }
}

uint32_t nrf_esb_write_payload(nrf_esb_payload_t const * p_payload)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_payload);
    VERIFY_PAYLOAD_LENGTH(p_payload);
    VERIFY_FALSE(m_tx_fifo.count >= NRF_ESB_TX_FIFO_SIZE, NRF_ERROR_NO_MEM);
    VERIFY_TRUE(p_payload->pipe < NRF_ESB_PIPE_COUNT, NRF_ERROR_INVALID_PARAM);

    DISABLE_RF_IRQ();

    memcpy(m_tx_fifo.p_payload[m_tx_fifo.entry_point], p_payload, sizeof(nrf_esb_payload_t));

    m_pids[p_payload->pipe] = (m_pids[p_payload->pipe] + 1) % (NRF_ESB_PID_MAX + 1);
    m_tx_fifo.p_payload[m_tx_fifo.entry_point]->pid = m_pids[p_payload->pipe];

    if (++m_tx_fifo.entry_point >= NRF_ESB_TX_FIFO_SIZE)
    {
        m_tx_fifo.entry_point = 0;
    }

    m_tx_fifo.count++;

    ENABLE_RF_IRQ();


    if (m_config_local.mode == NRF_ESB_MODE_PTX &&
        m_config_local.tx_mode == NRF_ESB_TXMODE_AUTO &&
        m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE)
    {
        start_tx_transaction();
    }

    return NRF_SUCCESS;
}


uint32_t nrf_esb_read_rx_payload(nrf_esb_payload_t * p_payload)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_payload);

    if (m_rx_fifo.count == 0)
    {
        return NRF_ERROR_NOT_FOUND;
    }

    DISABLE_RF_IRQ();

    p_payload->length = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->length;
    p_payload->pipe   = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->pipe;
    p_payload->rssi   = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->rssi;
    p_payload->pid    = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->pid;
    p_payload->noack  = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->noack; 
    memcpy(p_payload->data, m_rx_fifo.p_payload[m_rx_fifo.exit_point]->data, p_payload->length);

    if (++m_rx_fifo.exit_point >= NRF_ESB_RX_FIFO_SIZE)
    {
        m_rx_fifo.exit_point = 0;
    }

    m_rx_fifo.count--;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_start_tx(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    if (m_tx_fifo.count == 0)
    {
        return NRF_ERROR_BUFFER_EMPTY;
    }

    start_tx_transaction();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_start_rx(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    NRF_RADIO->INTENCLR = 0xFFFFFFFF;
    NRF_RADIO->EVENTS_DISABLED = 0;
    on_radio_disabled = on_radio_disabled_rx;

    NRF_RADIO->SHORTS      = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;
    NRF_RADIO->INTENSET    = RADIO_INTENSET_DISABLED_Msk;
    m_nrf_esb_mainstate    = NRF_ESB_STATE_PRX;

    NRF_RADIO->RXADDRESSES  = m_esb_addr.rx_pipes_enabled;
    NRF_RADIO->FREQUENCY    = m_esb_addr.rf_channel;
    NRF_RADIO->PACKETPTR    = (uint32_t)m_rx_payload_buffer;

    NVIC_ClearPendingIRQ(RADIO_IRQn);
    NVIC_EnableIRQ(RADIO_IRQn);

    NRF_RADIO->EVENTS_ADDRESS = 0;
    NRF_RADIO->EVENTS_PAYLOAD = 0;
    NRF_RADIO->EVENTS_DISABLED = 0;

    NRF_RADIO->TASKS_RXEN  = 1;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_stop_rx(void)
{
    if (m_nrf_esb_mainstate == NRF_ESB_STATE_PRX)
    {
        NRF_RADIO->SHORTS = 0;
        NRF_RADIO->INTENCLR = 0xFFFFFFFF;
        on_radio_disabled = NULL;
        NRF_RADIO->EVENTS_DISABLED = 0;
        NRF_RADIO->TASKS_DISABLE = 1;
        while (NRF_RADIO->EVENTS_DISABLED == 0);
        m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

        return NRF_SUCCESS;
    }

    return NRF_ESB_ERROR_NOT_IN_RX_MODE;
}


uint32_t nrf_esb_flush_tx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);

    DISABLE_RF_IRQ();

    m_tx_fifo.count = 0;
    m_tx_fifo.entry_point = 0;
    m_tx_fifo.exit_point = 0;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_pop_tx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_TRUE(m_tx_fifo.count > 0, NRF_ERROR_BUFFER_EMPTY);

    DISABLE_RF_IRQ();

    if (++m_tx_fifo.entry_point >= NRF_ESB_TX_FIFO_SIZE)
    {
        m_tx_fifo.entry_point = 0;
    }
    m_tx_fifo.count--;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_flush_rx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);

    DISABLE_RF_IRQ();

    m_rx_fifo.count = 0;
    m_rx_fifo.entry_point = 0;
    m_rx_fifo.exit_point = 0;

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_address_length(uint8_t length)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(length > 2 && length < 6, NRF_ERROR_INVALID_PARAM);
    
    /* 
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((NRF_RADIO->BASE0 & base_address_mask) == 0 && (NRF_RADIO->PREFIX0 & 0x000000FF) == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    if((NRF_RADIO->BASE1 & base_address_mask) == 0 && ((NRF_RADIO->PREFIX0 & 0x0000FF00) == 0 ||(NRF_RADIO->PREFIX0 & 0x00FF0000) == 0 || (NRF_RADIO->PREFIX0 & 0xFF000000) == 0 ||
       (NRF_RADIO->PREFIX1 & 0xFF000000) == 0 || (NRF_RADIO->PREFIX1 & 0x00FF0000) == 0 ||(NRF_RADIO->PREFIX1 & 0x0000FF00) == 0 || (NRF_RADIO->PREFIX1 & 0x000000FF) == 0))
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    m_esb_addr.addr_length = length;

    update_rf_payload_format(m_config_local.payload_length);

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_base_address_0(uint8_t const * p_addr)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_addr);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((addr_conv(p_addr) & base_address_mask) == 0 && (NRF_RADIO->PREFIX0 & 0x000000FF) == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

    memcpy(m_esb_addr.base_addr_p0, p_addr, 4);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE0);

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_base_address_1(uint8_t const * p_addr)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_addr);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((addr_conv(p_addr) & base_address_mask) == 0 && ((NRF_RADIO->PREFIX0 & 0x0000FF00) == 0 ||(NRF_RADIO->PREFIX0 & 0x00FF0000) == 0 || (NRF_RADIO->PREFIX0 & 0xFF000000) == 0 ||
       (NRF_RADIO->PREFIX1 & 0xFF000000) == 0 || (NRF_RADIO->PREFIX1 & 0x00FF0000) == 0 ||(NRF_RADIO->PREFIX1 & 0x0000FF00) == 0 || (NRF_RADIO->PREFIX1 & 0x000000FF) == 0))
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    memcpy(m_esb_addr.base_addr_p1, p_addr, 4);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE1);

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_prefixes(uint8_t const * p_prefixes, uint8_t num_pipes)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_prefixes);
    VERIFY_TRUE(num_pipes < 9, NRF_ERROR_INVALID_PARAM);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if(num_pipes >= 1 && (NRF_RADIO->BASE0 & base_address_mask) == 0 && p_prefixes[0] == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

    if((NRF_RADIO->BASE1 & base_address_mask) == 0)
    {
        for (uint8_t i = 1; i < num_pipes; i++)
        {
            if (p_prefixes[i] == 0)
            {
                return NRF_ERROR_INVALID_PARAM;
            }
        }
    }
    
    memcpy(m_esb_addr.pipe_prefixes, p_prefixes, num_pipes);
    m_esb_addr.num_pipes = num_pipes;
    m_esb_addr.rx_pipes_enabled = BIT_MASK_UINT_8(num_pipes);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_PREFIX);

    return apply_address_workarounds();
}


uint32_t nrf_esb_update_prefix(uint8_t pipe, uint8_t prefix)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(pipe < 8, NRF_ERROR_INVALID_PARAM);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if (pipe == 0)
    {
        if((NRF_RADIO->BASE0 & base_address_mask) == 0 && prefix == 0)
        {
            return NRF_ERROR_INVALID_PARAM;
        }
    }
    else{
        if((NRF_RADIO->BASE1 & base_address_mask) == 0 && prefix == 0)
        {
            return NRF_ERROR_INVALID_PARAM;
        }
    }
    
    m_esb_addr.pipe_prefixes[pipe] = prefix;

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_PREFIX);

    return apply_address_workarounds();
}


uint32_t nrf_esb_enable_pipes(uint8_t enable_mask)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_esb_addr.rx_pipes_enabled = enable_mask;

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_rf_channel(uint32_t channel)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(channel <= 100, NRF_ERROR_INVALID_PARAM);

    m_esb_addr.rf_channel = channel;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_get_rf_channel(uint32_t * p_channel)
{
    VERIFY_PARAM_NOT_NULL(p_channel);

    *p_channel = m_esb_addr.rf_channel;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_tx_power(nrf_esb_tx_power_t tx_output_power)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    if ( m_config_local.tx_output_power != tx_output_power )
    {
        m_config_local.tx_output_power = tx_output_power;
        update_radio_tx_power();
    }

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_retransmit_delay(uint16_t delay)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(delay >= NRF_ESB_RETRANSMIT_DELAY_MIN, NRF_ERROR_INVALID_PARAM);

    m_config_local.retransmit_delay = delay;
    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_retransmit_count(uint16_t count)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_config_local.retransmit_count = count;
    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_bitrate(nrf_esb_bitrate_t bitrate)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_config_local.bitrate = bitrate;
    return update_radio_bitrate() ? NRF_SUCCESS : NRF_ERROR_INVALID_PARAM;
}


uint32_t nrf_esb_reuse_pid(uint8_t pipe)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(pipe < 8, NRF_ERROR_INVALID_PARAM);

    m_pids[pipe] = (m_pids[pipe] + NRF_ESB_PID_MAX) % (NRF_ESB_PID_MAX + 1);
    return NRF_SUCCESS;
}


// Handler for 
#ifdef NRF52
void NRF_ESB_BUGFIX_TIMER_IRQHandler(void)
{
    if(NRF_ESB_BUGFIX_TIMER->EVENTS_COMPARE[0])
    {
        NRF_ESB_BUGFIX_TIMER->EVENTS_COMPARE[0] = 0;

        // If the timeout timer fires and we are in the PTX receive ACK state, disable the radio
        if(m_nrf_esb_mainstate == NRF_ESB_STATE_PTX_RX_ACK)
        {
            NRF_RADIO->TASKS_DISABLE = 1;
        }
    }
}
#endif

[fangrui166]

if i set NRF_ESB_MAX_PAYLOAD_LENGTH = 128 , this setting cannot work , could you help me check ?

[Sigurd]

Yes, I see that this causes some issues. I will take a look, and see if I can find the bug.

[Sigurd]

Hi,

I have not gotten to the bottom of why it didn’t work with payload larger than 32, and TxAdd bit set to 0.

But the workaround seem to be to set the TxAddBit to 1 instead, and use

NRF_RADIO->DACNF |= (1U << (pipe + RADIO_DACNF_TXADD0_Pos));

In radio_whitelist_add()

This will also require some minor changes in nrf_esb.c, where we instead of setting S0 byte to 0x00, we set it to e.g 0xFF instead, so that the TxAddbit (bit number 6 in S0) is 1. Below is the modified nrf_esb.c based on SDK 14.2, where we set S0 byte to 0xFF instead.

/**
 * Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
 * 
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 * 
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 * 
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 * 
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 * 
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 * 
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * 
 */

#include "nrf_error.h"
#include "nrf_esb.h"
#include "nrf_esb_error_codes.h"
#include "nrf_gpio.h"
#include <string.h>
#include <stddef.h>
#include "sdk_common.h"
#include "sdk_macros.h"
#include "app_util.h"
#include "nrf_log.h"
#include "nrf_delay.h"

#define BIT_MASK_UINT_8(x) (0xFF >> (8 - (x)))
#define NRF_ESB_PIPE_COUNT 8

#define S0BYTE 0xFF

// Constant parameters
#define RX_WAIT_FOR_ACK_TIMEOUT_US_2MBPS        (48)        /**< 2 Mb RX wait for acknowledgment time-out value. Smallest reliable value - 43. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS        (64)        /**< 1 Mb RX wait for acknowledgment time-out value. Smallest reliable value - 59. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_250KBPS      (250)       /**< 250 Kb RX wait for acknowledgment time-out value. */
#define RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS_BLE    (73)        /**< 1 Mb RX wait for acknowledgment time-out (combined with BLE). Smallest reliable value - 68.*/

// Interrupt flags
#define     NRF_ESB_INT_TX_SUCCESS_MSK          0x01        /**< Interrupt mask value for TX success. */
#define     NRF_ESB_INT_TX_FAILED_MSK           0x02        /**< Interrupt mask value for TX failure. */
#define     NRF_ESB_INT_RX_DATA_RECEIVED_MSK    0x04        /**< Interrupt mask value for RX_DR. */

#define     NRF_ESB_PID_RESET_VALUE             0xFF        /**< Invalid PID value which is guaranteed to not collide with any valid PID value. */
#define     NRF_ESB_PID_MAX                     3           /**< Maximum value for PID. */
#define     NRF_ESB_CRC_RESET_VALUE             0xFFFF      /**< CRC reset value. */

// Internal Enhanced ShockBurst module state.
typedef enum {
    NRF_ESB_STATE_IDLE,                                     /**< Module idle. */
    NRF_ESB_STATE_PTX_TX,                                   /**< Module transmitting without acknowledgment. */
    NRF_ESB_STATE_PTX_TX_ACK,                               /**< Module transmitting with acknowledgment. */
    NRF_ESB_STATE_PTX_RX_ACK,                               /**< Module transmitting with acknowledgment and reception of payload with the acknowledgment response. */
    NRF_ESB_STATE_PRX,                                      /**< Module receiving packets without acknowledgment. */
    NRF_ESB_STATE_PRX_SEND_ACK,                             /**< Module transmitting acknowledgment in RX mode. */
} nrf_esb_mainstate_t;


#define DISABLE_RF_IRQ()      NVIC_DisableIRQ(RADIO_IRQn)
#define ENABLE_RF_IRQ()       NVIC_EnableIRQ(RADIO_IRQn)

#define _RADIO_SHORTS_COMMON ( RADIO_SHORTS_READY_START_Msk | RADIO_SHORTS_END_DISABLE_Msk | \
            RADIO_SHORTS_ADDRESS_RSSISTART_Msk | RADIO_SHORTS_DISABLED_RSSISTOP_Msk )

#define VERIFY_PAYLOAD_LENGTH(p)                            \
do                                                          \
{                                                           \
    if (p->length == 0 ||                                    \
       p->length > NRF_ESB_MAX_PAYLOAD_LENGTH ||            \
       (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB &&  \
        p->length > m_config_local.payload_length))         \
    {                                                       \
        return NRF_ERROR_INVALID_LENGTH;                    \
    }                                                       \
}while (0)


/* @brief Structure holding pipe info PID and CRC and acknowledgment payload. */
typedef struct
{
    uint16_t    crc;                                      /**< CRC value of the last received packet (Used to detect retransmits). */
    uint8_t     pid;                                      /**< Packet ID of the last received packet (Used to detect retransmits). */
    bool        ack_payload;                              /**< Flag indicating the state of the transmission of acknowledgment payloads. */
	uint8_t     s0;
} pipe_info_t;


/* @brief  First-in, first-out queue of payloads to be transmitted. */
typedef struct
{
    nrf_esb_payload_t * p_payload[NRF_ESB_TX_FIFO_SIZE];  /**< Pointer to the actual queue. */
    uint32_t            entry_point;                      /**< Current start of queue. */
    uint32_t            exit_point;                       /**< Current end of queue. */
    uint32_t            count;                            /**< Current number of elements in the queue. */
} nrf_esb_payload_tx_fifo_t;


/* @brief First-in, first-out queue of received payloads. */
typedef struct
{
    nrf_esb_payload_t * p_payload[NRF_ESB_RX_FIFO_SIZE];  /**< Pointer to the actual queue. */
    uint32_t            entry_point;                      /**< Current start of queue. */
    uint32_t            exit_point;                       /**< Current end of queue. */
    uint32_t            count;                            /**< Current number of elements in the queue. */
} nrf_esb_payload_rx_fifo_t;


/**@brief Enhanced ShockBurst address.
 *
 * Enhanced ShockBurst addresses consist of a base address and a prefix
 *          that is unique for each pipe. See @ref esb_addressing in the ESB user
 *          guide for more information.
*/
typedef struct
{
    uint8_t base_addr_p0[4];        /**< Base address for pipe 0 encoded in big endian. */
    uint8_t base_addr_p1[4];        /**< Base address for pipe 1-7 encoded in big endian. */
    uint8_t pipe_prefixes[8];       /**< Address prefix for pipe 0 to 7. */
    uint8_t num_pipes;              /**< Number of pipes available. */
    uint8_t addr_length;            /**< Length of the address including the prefix. */
    uint8_t rx_pipes_enabled;       /**< Bitfield for enabled pipes. */
    uint8_t rf_channel;             /**< Channel to use (must be between 0 and 100). */
} nrf_esb_address_t;


// Module state
static bool                         m_esb_initialized           = false;
static nrf_esb_mainstate_t          m_nrf_esb_mainstate         = NRF_ESB_STATE_IDLE;
static nrf_esb_payload_t          * mp_current_payload;

static nrf_esb_event_handler_t      m_event_handler;

// Address parameters
__ALIGN(4) static nrf_esb_address_t m_esb_addr = NRF_ESB_ADDR_DEFAULT;

// RF parameters
static nrf_esb_config_t             m_config_local;

// TX FIFO
static nrf_esb_payload_t            m_tx_fifo_payload[NRF_ESB_TX_FIFO_SIZE];
static nrf_esb_payload_tx_fifo_t    m_tx_fifo;

// RX FIFO
static nrf_esb_payload_t            m_rx_fifo_payload[NRF_ESB_RX_FIFO_SIZE];
static nrf_esb_payload_rx_fifo_t    m_rx_fifo;

// Payload buffers
static  uint8_t                     m_tx_payload_buffer[NRF_ESB_MAX_PAYLOAD_LENGTH + 3]; //Added 1 for S0
static  uint8_t                     m_rx_payload_buffer[NRF_ESB_MAX_PAYLOAD_LENGTH + 3]; //Added 1 for S0

// Run time variables
static volatile uint32_t            m_interrupt_flags = 0;
static uint8_t                      m_pids[NRF_ESB_PIPE_COUNT];
static pipe_info_t                  m_rx_pipe_info[NRF_ESB_PIPE_COUNT];
static volatile uint32_t            m_retransmits_remaining;
static volatile uint32_t            m_last_tx_attempts;
static volatile uint32_t            m_wait_for_ack_timeout_us;

// nRF52 address workaround enable
#ifdef NRF52
static bool                         m_address_hang_fix_enable = true;
#endif
static uint32_t                     m_radio_shorts_common = _RADIO_SHORTS_COMMON;

// These function pointers are changed dynamically, depending on protocol configuration and state.
static void (*on_radio_disabled)(void) = 0;
static void (*on_radio_end)(void) = 0;
static void (*update_rf_payload_format)(uint32_t payload_length) = 0;


// The following functions are assigned to the function pointers above.
static void on_radio_disabled_tx_noack(void);
static void on_radio_disabled_tx(void);
static void on_radio_disabled_tx_wait_for_ack(void);
static void on_radio_disabled_rx(void);
static void on_radio_disabled_rx_ack(void);


#define NRF_ESB_ADDR_UPDATE_MASK_BASE0          (1 << 0)    /*< Mask value to signal updating BASE0 radio address. */
#define NRF_ESB_ADDR_UPDATE_MASK_BASE1          (1 << 1)    /*< Mask value to signal updating BASE1 radio address. */
#define NRF_ESB_ADDR_UPDATE_MASK_PREFIX         (1 << 2)    /*< Mask value to signal updating radio prefixes. */


// Function to do bytewise bit-swap on an unsigned 32-bit value
static uint32_t bytewise_bit_swap(uint8_t const * p_inp)
{
    uint32_t inp = (*(uint32_t*)p_inp);
#if __CORTEX_M == (0x04U)
    return __REV((uint32_t)__RBIT(inp)); //lint -esym(628, __rev) -esym(526, __rev) -esym(628, __rbit) -esym(526, __rbit) */
#else
    inp = (inp & 0xF0F0F0F0) >> 4 | (inp & 0x0F0F0F0F) << 4;
    inp = (inp & 0xCCCCCCCC) >> 2 | (inp & 0x33333333) << 2;
    inp = (inp & 0xAAAAAAAA) >> 1 | (inp & 0x55555555) << 1;
    return inp;
#endif
}


// Internal function to convert base addresses from nRF24L type addressing to nRF51 type addressing
static uint32_t addr_conv(uint8_t const* p_addr)
{
    return __REV(bytewise_bit_swap(p_addr)); //lint -esym(628, __rev) -esym(526, __rev) */
}


static ret_code_t apply_address_workarounds()
{
#ifdef NRF52
    //  Set up radio parameters.
    NRF_RADIO->MODECNF0 = (NRF_RADIO->MODECNF0 & ~RADIO_MODECNF0_RU_Msk) | RADIO_MODECNF0_RU_Default << RADIO_MODECNF0_RU_Pos;

    // Workaround for nRF52832 Rev 1 Errata 102 and nRF52832 Rev 1 Errata 106. This will reduce sensitivity by 3dB.
    *((volatile uint32_t *)0x40001774) = (*((volatile uint32_t *)0x40001774) & 0xFFFFFFFE) | 0x01000000;
#endif
    return NRF_SUCCESS;
}


static void update_rf_payload_format_esb_dpl(uint32_t payload_length)
{
#if (NRF_ESB_MAX_PAYLOAD_LENGTH <= 32)
    // Using 6 bits for length
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |  //Setting 1 for S0 byte
                       (6 << RADIO_PCNF0_LFLEN_Pos) |
                       (3 << RADIO_PCNF0_S1LEN_Pos) ;
#else
    // Using 8 bits for length
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |  //Setting 1 for S0 byte
                       (8 << RADIO_PCNF0_LFLEN_Pos) |
                       (3 << RADIO_PCNF0_S1LEN_Pos) ;
#endif
    NRF_RADIO->PCNF1 = (RADIO_PCNF1_WHITEEN_Disabled    << RADIO_PCNF1_WHITEEN_Pos) |
                       (RADIO_PCNF1_ENDIAN_Little          << RADIO_PCNF1_ENDIAN_Pos)  |
                       ((m_esb_addr.addr_length - 1)    << RADIO_PCNF1_BALEN_Pos)   |
                       (0                               << RADIO_PCNF1_STATLEN_Pos) |
                       (NRF_ESB_MAX_PAYLOAD_LENGTH      << RADIO_PCNF1_MAXLEN_Pos);
}


static void update_rf_payload_format_esb(uint32_t payload_length)
{
    NRF_RADIO->PCNF0 = (1 << RADIO_PCNF0_S0LEN_Pos) |
                       (0 << RADIO_PCNF0_LFLEN_Pos) |
                       (1 << RADIO_PCNF0_S1LEN_Pos);

    NRF_RADIO->PCNF1 = (RADIO_PCNF1_WHITEEN_Disabled    << RADIO_PCNF1_WHITEEN_Pos) |
                       (RADIO_PCNF1_ENDIAN_Little          << RADIO_PCNF1_ENDIAN_Pos)  |
                       ((m_esb_addr.addr_length - 1)    << RADIO_PCNF1_BALEN_Pos)   |
                       (payload_length                  << RADIO_PCNF1_STATLEN_Pos) |
                       (payload_length                  << RADIO_PCNF1_MAXLEN_Pos);
}


static void update_radio_addresses(uint8_t update_mask)
{
    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_BASE0) != 0)
    {
        NRF_RADIO->BASE0 = addr_conv(m_esb_addr.base_addr_p0);
    }

    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_BASE1) != 0)
    {
        NRF_RADIO->BASE1 = addr_conv(m_esb_addr.base_addr_p1);
    }

    if ((update_mask & NRF_ESB_ADDR_UPDATE_MASK_PREFIX) != 0)
    {
        NRF_RADIO->PREFIX0 = bytewise_bit_swap(&m_esb_addr.pipe_prefixes[0]);
        NRF_RADIO->PREFIX1 = bytewise_bit_swap(&m_esb_addr.pipe_prefixes[4]);
    }
}


static void update_radio_tx_power()
{
    NRF_RADIO->TXPOWER = m_config_local.tx_output_power << RADIO_TXPOWER_TXPOWER_Pos;
}


static bool update_radio_bitrate()
{
    NRF_RADIO->MODE = m_config_local.bitrate << RADIO_MODE_MODE_Pos;

    switch (m_config_local.bitrate)
    {
        case NRF_ESB_BITRATE_2MBPS:
#ifdef NRF52
        case NRF_ESB_BITRATE_2MBPS_BLE:
#endif
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_2MBPS;
            break;

        case NRF_ESB_BITRATE_1MBPS:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS;
            break;

#ifdef NRF51
        case NRF_ESB_BITRATE_250KBPS:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_250KBPS;
            break;
#endif
        
        case NRF_ESB_BITRATE_1MBPS_BLE:
            m_wait_for_ack_timeout_us = RX_WAIT_FOR_ACK_TIMEOUT_US_1MBPS_BLE;
            break;

        default:
            // Should not be reached
            return false;
    }
    return true;
}


static bool update_radio_protocol()
{
    switch (m_config_local.protocol)
    {
        case NRF_ESB_PROTOCOL_ESB_DPL:
            update_rf_payload_format = update_rf_payload_format_esb_dpl;
            break;

        case NRF_ESB_PROTOCOL_ESB:
            update_rf_payload_format = update_rf_payload_format_esb;
            break;

        default:
            // Should not be reached
            return false;
    }
    return true;
}


static bool update_radio_crc()
{
    switch(m_config_local.crc)
    {
        case NRF_ESB_CRC_16BIT:
            NRF_RADIO->CRCINIT = 0xFFFFUL;      // Initial value
            NRF_RADIO->CRCPOLY = 0x11021UL;     // CRC poly: x^16+x^12^x^5+1
            break;
        
        case NRF_ESB_CRC_8BIT:
            NRF_RADIO->CRCINIT = 0xFFUL;        // Initial value
            NRF_RADIO->CRCPOLY = 0x107UL;       // CRC poly: x^8+x^2^x^1+1
            break;
        
        case NRF_ESB_CRC_OFF:
            break;
        
        default:
            return false;
    }
    NRF_RADIO->CRCCNF = m_config_local.crc << RADIO_CRCCNF_LEN_Pos;
    return true;
}


static bool update_radio_parameters()
{
    bool params_valid = true;
    update_radio_tx_power();
    params_valid &= update_radio_bitrate();
    params_valid &= update_radio_protocol();
    params_valid &= update_radio_crc();
    update_rf_payload_format(m_config_local.payload_length);
    params_valid &= (m_config_local.retransmit_delay >= NRF_ESB_RETRANSMIT_DELAY_MIN);
    return params_valid;
}


static void reset_fifos()
{
    m_tx_fifo.entry_point = 0;
    m_tx_fifo.exit_point  = 0;
    m_tx_fifo.count       = 0;

    m_rx_fifo.entry_point = 0;
    m_rx_fifo.exit_point  = 0;
    m_rx_fifo.count       = 0;
}


static void initialize_fifos()
{
    reset_fifos();

    for (int i = 0; i < NRF_ESB_TX_FIFO_SIZE; i++)
    {
        m_tx_fifo.p_payload[i] = &m_tx_fifo_payload[i];
    }

    for (int i = 0; i < NRF_ESB_RX_FIFO_SIZE; i++)
    {
        m_rx_fifo.p_payload[i] = &m_rx_fifo_payload[i];
    }
}


static void tx_fifo_remove_last()
{
    if (m_tx_fifo.count > 0)
    {
        DISABLE_RF_IRQ();

        m_tx_fifo.count--;
        if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
        {
            m_tx_fifo.exit_point = 0;
        }

        ENABLE_RF_IRQ();
    }
}

/** @brief  Function to push the content of the rx_buffer to the RX FIFO.
 *
 *  The module will point the register NRF_RADIO->PACKETPTR to a buffer for receiving packets.
 *  After receiving a packet the module will call this function to copy the received data to
 *  the RX FIFO.
 *
 *  @param  pipe Pipe number to set for the packet.
 *  @param  pid  Packet ID.
 *
 *  @retval true   Operation successful.
 *  @retval false  Operation failed.
 */
static bool rx_fifo_push_rfbuf(uint8_t pipe, uint8_t pid)
{
    if (m_rx_fifo.count < NRF_ESB_RX_FIFO_SIZE)
    {
        if (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB_DPL)
        {
            if (m_rx_payload_buffer[1] > NRF_ESB_MAX_PAYLOAD_LENGTH) //Moved 1 byte. Changed from 0 to 1.
            {
                return false;
            }

            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = m_rx_payload_buffer[1]; //Length is moved 1 byte because of S0. Changed from 0 to 1
        }
        else if (m_config_local.mode == NRF_ESB_MODE_PTX)
        {
            // Received packet is an acknowledgment
            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = 0;
        }
        else
        {
            m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = m_config_local.payload_length;
        }

        memcpy(m_rx_fifo.p_payload[m_rx_fifo.entry_point]->data, &m_rx_payload_buffer[3], //Moved 1 byte. Changed from 2 to 3.
               m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length);

        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->pipe  = pipe;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->rssi  = NRF_RADIO->RSSISAMPLE;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->pid   = pid;
        m_rx_fifo.p_payload[m_rx_fifo.entry_point]->noack = !(m_rx_payload_buffer[2] & 0x01);  //moved 1 byte. Changed from 1 to 2.
        if (++m_rx_fifo.entry_point >= NRF_ESB_RX_FIFO_SIZE)
        {
            m_rx_fifo.entry_point = 0;
        }
        m_rx_fifo.count++;

        return true;
    }

    return false;
}


static void sys_timer_init()
{
    // Configure the system timer with a 1 MHz base frequency
    NRF_ESB_SYS_TIMER->PRESCALER = 4;
    NRF_ESB_SYS_TIMER->BITMODE   = TIMER_BITMODE_BITMODE_16Bit;
    NRF_ESB_SYS_TIMER->SHORTS    = TIMER_SHORTS_COMPARE1_CLEAR_Msk | TIMER_SHORTS_COMPARE1_STOP_Msk;
}


static void ppi_init()
{
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_START].EEP = (uint32_t)&NRF_RADIO->EVENTS_READY;
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_START].TEP = (uint32_t)&NRF_ESB_SYS_TIMER->TASKS_START;

    NRF_PPI->CH[NRF_ESB_PPI_TIMER_STOP].EEP  = (uint32_t)&NRF_RADIO->EVENTS_ADDRESS;
    NRF_PPI->CH[NRF_ESB_PPI_TIMER_STOP].TEP  = (uint32_t)&NRF_ESB_SYS_TIMER->TASKS_STOP;

    NRF_PPI->CH[NRF_ESB_PPI_RX_TIMEOUT].EEP  = (uint32_t)&NRF_ESB_SYS_TIMER->EVENTS_COMPARE[0];
    NRF_PPI->CH[NRF_ESB_PPI_RX_TIMEOUT].TEP  = (uint32_t)&NRF_RADIO->TASKS_DISABLE;

    NRF_PPI->CH[NRF_ESB_PPI_TX_START].EEP    = (uint32_t)&NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1];
    NRF_PPI->CH[NRF_ESB_PPI_TX_START].TEP    = (uint32_t)&NRF_RADIO->TASKS_TXEN;
}


static void start_tx_transaction()
{
    bool ack;

    m_last_tx_attempts = 1;
    // Prepare the payload
    mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];


    switch (m_config_local.protocol)
    {
        case NRF_ESB_PROTOCOL_ESB: //We are using ESB_DPL. No changes done here.
            update_rf_payload_format(mp_current_payload->length);
            m_tx_payload_buffer[0] = mp_current_payload->pid;
            m_tx_payload_buffer[1] = 0;
            memcpy(&m_tx_payload_buffer[2], mp_current_payload->data, mp_current_payload->length);

            NRF_RADIO->SHORTS   = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
            NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk | RADIO_INTENSET_READY_Msk;

            // Configure the retransmit counter
            m_retransmits_remaining = m_config_local.retransmit_count;
            on_radio_disabled = on_radio_disabled_tx;
            m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            break;

        case NRF_ESB_PROTOCOL_ESB_DPL:
            ack = !mp_current_payload->noack || !m_config_local.selective_auto_ack;
	    m_tx_payload_buffer[0] = S0BYTE; //setting s0 as first byte in packet.
            m_tx_payload_buffer[1] = mp_current_payload->length; //Length has been moved 1 byte. Changed from 0 to 1.
            m_tx_payload_buffer[2] = mp_current_payload->pid << 1;  //Moved 1 byte. Changed from 1 to 2.
            m_tx_payload_buffer[2] |= mp_current_payload->noack ? 0x00 : 0x01; //Moved 1 byte. Changed from 1 to 2.
            memcpy(&m_tx_payload_buffer[3], mp_current_payload->data, mp_current_payload->length); //Moved 1 byte. Changed from 2 to 3.

            // Handling ack if noack is set to false or if selective auto ack is turned off
            if (ack)
            {
                NRF_RADIO->SHORTS   = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
                NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk | RADIO_INTENSET_READY_Msk;

                // Configure the retransmit counter
                m_retransmits_remaining = m_config_local.retransmit_count;
                on_radio_disabled = on_radio_disabled_tx;
                m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            }
            else
            {
                NRF_RADIO->SHORTS   = m_radio_shorts_common;
                NRF_RADIO->INTENSET = RADIO_INTENSET_DISABLED_Msk;
                on_radio_disabled   = on_radio_disabled_tx_noack;
                m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX;
            }
            break;

        default:
            // Should not be reached
            break;
    }

    NRF_RADIO->TXADDRESS    = mp_current_payload->pipe;
    NRF_RADIO->RXADDRESSES  = 1 << mp_current_payload->pipe;

    NRF_RADIO->FREQUENCY    = m_esb_addr.rf_channel;
    NRF_RADIO->PACKETPTR    = (uint32_t)m_tx_payload_buffer;

    NVIC_ClearPendingIRQ(RADIO_IRQn);
    NVIC_EnableIRQ(RADIO_IRQn);

    NRF_RADIO->EVENTS_ADDRESS = 0;
    NRF_RADIO->EVENTS_PAYLOAD = 0;
    NRF_RADIO->EVENTS_DISABLED = 0;

    DEBUG_PIN_SET(DEBUGPIN4);
    NRF_RADIO->TASKS_TXEN  = 1;
}


static void on_radio_disabled_tx_noack()
{
    m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
    tx_fifo_remove_last();

    if (m_tx_fifo.count == 0)
    {
        m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
        NVIC_SetPendingIRQ(ESB_EVT_IRQ);
    }
    else
    {
        NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        start_tx_transaction();
    }
}


static void on_radio_disabled_tx()
{
    // Remove the DISABLED -> RXEN shortcut, to make sure the radio stays
    // disabled after the RX window
    NRF_RADIO->SHORTS           = m_radio_shorts_common;

    // Make sure the timer is started the next time the radio is ready,
    // and that it will disable the radio automatically if no packet is
    // received by the time defined in m_wait_for_ack_timeout_us
    NRF_ESB_SYS_TIMER->CC[0]    = m_wait_for_ack_timeout_us;
    NRF_ESB_SYS_TIMER->CC[1]    = m_config_local.retransmit_delay - 130;
    NRF_ESB_SYS_TIMER->TASKS_CLEAR = 1;
    NRF_ESB_SYS_TIMER->EVENTS_COMPARE[0] = 0;
    NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1] = 0;

    NRF_PPI->CHENSET            = (1 << NRF_ESB_PPI_TIMER_START) |
                                  (1 << NRF_ESB_PPI_RX_TIMEOUT) |
                                  (1 << NRF_ESB_PPI_TIMER_STOP);
    NRF_PPI->CHENCLR            = (1 << NRF_ESB_PPI_TX_START);
    NRF_RADIO->EVENTS_END       = 0;

    if (m_config_local.protocol == NRF_ESB_PROTOCOL_ESB)
    {
        update_rf_payload_format(0);
    }

    NRF_RADIO->PACKETPTR        = (uint32_t)m_rx_payload_buffer;
    on_radio_disabled           = on_radio_disabled_tx_wait_for_ack;
    m_nrf_esb_mainstate         = NRF_ESB_STATE_PTX_RX_ACK;
}


static void on_radio_disabled_tx_wait_for_ack()
{
    // This marks the completion of a TX_RX sequence (TX with ACK)

    // Make sure the timer will not deactivate the radio if a packet is received
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TIMER_STOP);

    // If the radio has received a packet and the CRC status is OK
    if (NRF_RADIO->EVENTS_END && NRF_RADIO->CRCSTATUS != 0)
    {
        NRF_ESB_SYS_TIMER->TASKS_STOP = 1;
        NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TX_START);
        m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
        m_last_tx_attempts = m_config_local.retransmit_count - m_retransmits_remaining + 1;

        tx_fifo_remove_last();

        if (m_config_local.protocol != NRF_ESB_PROTOCOL_ESB && m_rx_payload_buffer[0] > 0)
        {
            if (rx_fifo_push_rfbuf((uint8_t)NRF_RADIO->TXADDRESS, m_rx_payload_buffer[1] >> 1))
            {
                m_interrupt_flags |= NRF_ESB_INT_RX_DATA_RECEIVED_MSK;
            }
        }

        if ((m_tx_fifo.count == 0) || (m_config_local.tx_mode == NRF_ESB_TXMODE_MANUAL))
        {
            m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
        else
        {
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
            start_tx_transaction();
        }
    }
    else
    {
        if (m_retransmits_remaining-- == 0)
        {
            NRF_ESB_SYS_TIMER->TASKS_STOP = 1;
            NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TX_START);
            // All retransmits are expended, and the TX operation is suspended
            m_last_tx_attempts = m_config_local.retransmit_count + 1;
            m_interrupt_flags |= NRF_ESB_INT_TX_FAILED_MSK;

            m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
        else
        {
            // There are still more retransmits left, TX mode should be
            // entered again as soon as the system timer reaches CC[1].
            NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;
            update_rf_payload_format(mp_current_payload->length);
            NRF_RADIO->PACKETPTR = (uint32_t)m_tx_payload_buffer;
            on_radio_disabled = on_radio_disabled_tx;
            m_nrf_esb_mainstate = NRF_ESB_STATE_PTX_TX_ACK;
            NRF_ESB_SYS_TIMER->TASKS_START = 1;
            NRF_PPI->CHENSET = (1 << NRF_ESB_PPI_TX_START);
            if (NRF_ESB_SYS_TIMER->EVENTS_COMPARE[1])
            {
                NRF_RADIO->TASKS_TXEN = 1;
            }
        }
    }
}

static void clear_events_restart_rx(void)
{
    NRF_RADIO->SHORTS = m_radio_shorts_common;
    update_rf_payload_format(m_config_local.payload_length);
    NRF_RADIO->PACKETPTR = (uint32_t)m_rx_payload_buffer;
    NRF_RADIO->EVENTS_DISABLED = 0;
    NRF_RADIO->TASKS_DISABLE = 1;

    while (NRF_RADIO->EVENTS_DISABLED == 0);

    NRF_RADIO->EVENTS_DISABLED = 0;
    NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;

    NRF_RADIO->TASKS_RXEN = 1;
}

static void on_radio_disabled_rx(void)
{
    bool            ack                = false;
    bool            retransmit_payload = false;
    bool            send_rx_event      = true;
    pipe_info_t *   p_pipe_info;

    if (NRF_RADIO->CRCSTATUS == 0)
    {
        clear_events_restart_rx();
        return;
    }

    if (m_rx_fifo.count >= NRF_ESB_RX_FIFO_SIZE)
    {
        clear_events_restart_rx();
        return;
    }

    p_pipe_info = &m_rx_pipe_info[NRF_RADIO->RXMATCH];
    if (NRF_RADIO->RXCRC             == p_pipe_info->crc &&
        (m_rx_payload_buffer[2] >> 1) == p_pipe_info->pid   //Moved 1 byte. Changed from 1 to 2.
       )
    {
        retransmit_payload = true;
        send_rx_event = false;
    }

    p_pipe_info->pid = m_rx_payload_buffer[2] >> 1;  //Moved 1 byte. Changed from 1 to 2.
    p_pipe_info->crc = NRF_RADIO->RXCRC;

    if ((m_config_local.selective_auto_ack == false) || ((m_rx_payload_buffer[2] & 0x01) == 1)) //Moved 1 byte. Changed from 1 to 2.
    {
        ack = true;
    }

    if (ack)
    {
        NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_RXEN_Msk;

        switch (m_config_local.protocol)
        {
            case NRF_ESB_PROTOCOL_ESB_DPL:
                {
                    if (m_tx_fifo.count > 0 &&
                        (m_tx_fifo.p_payload[m_tx_fifo.exit_point]->pipe == NRF_RADIO->RXMATCH)
                       )
                    {
                        // Pipe stays in ACK with payload until TX FIFO is empty
                        // Do not report TX success on first ack payload or retransmit
                        if (p_pipe_info->ack_payload == true && !retransmit_payload)
                        {
                            if (++m_tx_fifo.exit_point >= NRF_ESB_TX_FIFO_SIZE)
                            {
                                m_tx_fifo.exit_point = 0;
                            }

                            m_tx_fifo.count--;

                            // ACK payloads also require TX_DS
                            // (page 40 of the 'nRF24LE1_Product_Specification_rev1_6.pdf').
                            m_interrupt_flags |= NRF_ESB_INT_TX_SUCCESS_MSK;
                        }

                        p_pipe_info->ack_payload = true;

                        mp_current_payload = m_tx_fifo.p_payload[m_tx_fifo.exit_point];

                        update_rf_payload_format(mp_current_payload->length);
						m_tx_payload_buffer[0] = S0BYTE; // Setting to S0BYTE
                        m_tx_payload_buffer[1] = mp_current_payload->length;   //Moved 1 byte. Changed from 0 to 1.
                        memcpy(&m_tx_payload_buffer[3],   //Moved 1 byte. Changed from 2 to 3.
                               mp_current_payload->data,
                               mp_current_payload->length);
                    }
                    else
                    {
                        p_pipe_info->ack_payload = false;
                        update_rf_payload_format(0);
						m_tx_payload_buffer[0] = S0BYTE; // Setting to S0BYTE
                        m_tx_payload_buffer[1] = 0; //Moved 1 byte. Changed from 0 to 1.
                    }

                    m_tx_payload_buffer[2] = m_rx_payload_buffer[2]; //Moved 1 byte. Changed from 1 to 2.
                }
                break;

            case NRF_ESB_PROTOCOL_ESB: //Using DPL. No changes
                {
                    update_rf_payload_format(0);
                    m_tx_payload_buffer[0] = m_rx_payload_buffer[0];
                    m_tx_payload_buffer[1] = 0;
                }
                break;
        }

        m_nrf_esb_mainstate = NRF_ESB_STATE_PRX_SEND_ACK;
        NRF_RADIO->TXADDRESS = NRF_RADIO->RXMATCH;
        NRF_RADIO->PACKETPTR = (uint32_t)m_tx_payload_buffer;
        on_radio_disabled = on_radio_disabled_rx_ack;
    }
    else
    {
        clear_events_restart_rx();
    }

    if (send_rx_event)
    {
        // Push the new packet to the RX buffer and trigger a received event if the operation was
        // successful.
        if (rx_fifo_push_rfbuf(NRF_RADIO->RXMATCH, p_pipe_info->pid))
        {
            m_interrupt_flags |= NRF_ESB_INT_RX_DATA_RECEIVED_MSK;
            NVIC_SetPendingIRQ(ESB_EVT_IRQ);
        }
    }
}


static void on_radio_disabled_rx_ack(void)
{
    NRF_RADIO->SHORTS = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;
    update_rf_payload_format(m_config_local.payload_length);

    NRF_RADIO->PACKETPTR = (uint32_t)m_rx_payload_buffer;
    on_radio_disabled = on_radio_disabled_rx;

    m_nrf_esb_mainstate = NRF_ESB_STATE_PRX;
}


/**@brief Function for clearing pending interrupts.
 *
 * @param[in,out]   p_interrupts        Pointer to the value that holds the current interrupts.
 *
 * @retval  NRF_SUCCESS                     If the interrupts were cleared successfully.
 * @retval  NRF_ERROR_NULL                  If the required parameter was NULL.
 * @retval  NRF_INVALID_STATE               If the module is not initialized.
 */
static uint32_t nrf_esb_get_clear_interrupts(uint32_t * p_interrupts)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_interrupts);

    DISABLE_RF_IRQ();

    *p_interrupts = m_interrupt_flags;
    m_interrupt_flags = 0;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


void RADIO_IRQHandler()
{
    if (NRF_RADIO->EVENTS_READY && (NRF_RADIO->INTENSET & RADIO_INTENSET_READY_Msk))
    {
        NRF_RADIO->EVENTS_READY = 0;
        DEBUG_PIN_SET(DEBUGPIN1);
    }

    if (NRF_RADIO->EVENTS_END && (NRF_RADIO->INTENSET & RADIO_INTENSET_END_Msk))
    {
        NRF_RADIO->EVENTS_END = 0;
        DEBUG_PIN_SET(DEBUGPIN2);

        // Call the correct on_radio_end function, depending on the current protocol state
        if (on_radio_end)
        {
            on_radio_end();
        }
    }

    if (NRF_RADIO->EVENTS_DISABLED && (NRF_RADIO->INTENSET & RADIO_INTENSET_DISABLED_Msk))
    {
        NRF_RADIO->EVENTS_DISABLED = 0;
        DEBUG_PIN_SET(DEBUGPIN3);

        // Call the correct on_radio_disable function, depending on the current protocol state
        if (on_radio_disabled)
        {
            on_radio_disabled();
        }
    }

    DEBUG_PIN_CLR(DEBUGPIN1);
    DEBUG_PIN_CLR(DEBUGPIN2);
    DEBUG_PIN_CLR(DEBUGPIN3);
    DEBUG_PIN_CLR(DEBUGPIN4);
}


uint32_t nrf_esb_init(nrf_esb_config_t const * p_config)
{
    uint32_t err_code;

    VERIFY_PARAM_NOT_NULL(p_config);

    if (m_esb_initialized)
    {
        err_code = nrf_esb_disable();
        if (err_code != NRF_SUCCESS)
        {
            return err_code;
        }
    }

    m_event_handler = p_config->event_handler;

    memcpy(&m_config_local, p_config, sizeof(nrf_esb_config_t));
    
    m_interrupt_flags    = 0;

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));
    memset(m_pids, 0, sizeof(m_pids));

    VERIFY_TRUE(update_radio_parameters(), NRF_ERROR_INVALID_PARAM);

    // Configure radio address registers according to ESB default values
    NRF_RADIO->BASE0   = 0xE7E7E7E7;
    NRF_RADIO->BASE1   = 0x43434343;
    NRF_RADIO->PREFIX0 = 0x23C343E7;
    NRF_RADIO->PREFIX1 = 0x13E363A3;
    
    initialize_fifos();

    sys_timer_init();

    ppi_init();

    NVIC_SetPriority(RADIO_IRQn, m_config_local.radio_irq_priority & ESB_IRQ_PRIORITY_MSK);
    NVIC_SetPriority(ESB_EVT_IRQ, m_config_local.event_irq_priority & ESB_IRQ_PRIORITY_MSK);
    NVIC_EnableIRQ(ESB_EVT_IRQ);

#ifdef NRF52
    if(m_address_hang_fix_enable)
    {
        // Setup a timeout timer to start on an ADDRESS match, and stop on a BCMATCH event.
        // If the BCMATCH event never occurs the CC[0] event will fire, and the timer interrupt will disable the radio to recover.
        m_radio_shorts_common |= RADIO_SHORTS_ADDRESS_BCSTART_Msk;
        NRF_RADIO->BCC = 2;
        NRF_ESB_BUGFIX_TIMER->BITMODE = TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos;
        NRF_ESB_BUGFIX_TIMER->PRESCALER = 4;
        NRF_ESB_BUGFIX_TIMER->CC[0] = 5;
        NRF_ESB_BUGFIX_TIMER->SHORTS = TIMER_SHORTS_COMPARE0_STOP_Msk | TIMER_SHORTS_COMPARE0_CLEAR_Msk;
        NRF_ESB_BUGFIX_TIMER->MODE = TIMER_MODE_MODE_Timer << TIMER_MODE_MODE_Pos;
        NRF_ESB_BUGFIX_TIMER->INTENSET = TIMER_INTENSET_COMPARE0_Msk;
        NRF_ESB_BUGFIX_TIMER->TASKS_CLEAR = 1;
        NVIC_SetPriority(NRF_ESB_BUGFIX_TIMER_IRQn, 5);
        NVIC_EnableIRQ(NRF_ESB_BUGFIX_TIMER_IRQn);

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX1].EEP = (uint32_t)&NRF_RADIO->EVENTS_ADDRESS;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX1].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_START;

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX2].EEP = (uint32_t)&NRF_RADIO->EVENTS_BCMATCH;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX2].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_STOP;

        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX3].EEP = (uint32_t)&NRF_RADIO->EVENTS_BCMATCH;
        NRF_PPI->CH[NRF_ESB_PPI_BUGFIX3].TEP = (uint32_t)&NRF_ESB_BUGFIX_TIMER->TASKS_CLEAR;

        NRF_PPI->CHENSET = (1 << NRF_ESB_PPI_BUGFIX1) | (1 << NRF_ESB_PPI_BUGFIX2) | (1 << NRF_ESB_PPI_BUGFIX3);
    }
#endif

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
    m_esb_initialized = true;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_suspend(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    // Clear PPI
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_TIMER_STOP)  |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TX_START);

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_disable(void)
{
    // Clear PPI
    NRF_PPI->CHENCLR = (1 << NRF_ESB_PPI_TIMER_START) |
                       (1 << NRF_ESB_PPI_TIMER_STOP)  |
                       (1 << NRF_ESB_PPI_RX_TIMEOUT)  |
                       (1 << NRF_ESB_PPI_TX_START);

    m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

    reset_fifos();

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));
    memset(m_pids, 0, sizeof(m_pids));

    // Disable the radio
    NVIC_DisableIRQ(ESB_EVT_IRQ);
    NRF_RADIO->SHORTS = RADIO_SHORTS_READY_START_Enabled << RADIO_SHORTS_READY_START_Pos |
                        RADIO_SHORTS_END_DISABLE_Enabled << RADIO_SHORTS_END_DISABLE_Pos;

    return NRF_SUCCESS;
}


bool nrf_esb_is_idle(void)
{
    return m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE;
}


void ESB_EVT_IRQHandler(void)
{
    ret_code_t      err_code;
    uint32_t        interrupts;
    nrf_esb_evt_t   event;

    event.tx_attempts = m_last_tx_attempts;

    err_code = nrf_esb_get_clear_interrupts(&interrupts);
    if (err_code == NRF_SUCCESS && m_event_handler != 0)
    {
        if (interrupts & NRF_ESB_INT_TX_SUCCESS_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_TX_SUCCESS;
            m_event_handler(&event);
        }
        if (interrupts & NRF_ESB_INT_TX_FAILED_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_TX_FAILED;
            m_event_handler(&event);
        }
        if (interrupts & NRF_ESB_INT_RX_DATA_RECEIVED_MSK)
        {
            event.evt_id = NRF_ESB_EVENT_RX_RECEIVED;
            m_event_handler(&event);
        }
    }
}

uint32_t nrf_esb_write_payload(nrf_esb_payload_t const * p_payload)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_payload);
    VERIFY_PAYLOAD_LENGTH(p_payload);
    VERIFY_FALSE(m_tx_fifo.count >= NRF_ESB_TX_FIFO_SIZE, NRF_ERROR_NO_MEM);
    VERIFY_TRUE(p_payload->pipe < NRF_ESB_PIPE_COUNT, NRF_ERROR_INVALID_PARAM);

    DISABLE_RF_IRQ();

    memcpy(m_tx_fifo.p_payload[m_tx_fifo.entry_point], p_payload, sizeof(nrf_esb_payload_t));

    m_pids[p_payload->pipe] = (m_pids[p_payload->pipe] + 1) % (NRF_ESB_PID_MAX + 1);
    m_tx_fifo.p_payload[m_tx_fifo.entry_point]->pid = m_pids[p_payload->pipe];

    if (++m_tx_fifo.entry_point >= NRF_ESB_TX_FIFO_SIZE)
    {
        m_tx_fifo.entry_point = 0;
    }

    m_tx_fifo.count++;

    ENABLE_RF_IRQ();


    if (m_config_local.mode == NRF_ESB_MODE_PTX &&
        m_config_local.tx_mode == NRF_ESB_TXMODE_AUTO &&
        m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE)
    {
        start_tx_transaction();
    }

    return NRF_SUCCESS;
}


uint32_t nrf_esb_read_rx_payload(nrf_esb_payload_t * p_payload)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_PARAM_NOT_NULL(p_payload);

    if (m_rx_fifo.count == 0)
    {
        return NRF_ERROR_NOT_FOUND;
    }

    DISABLE_RF_IRQ();

    p_payload->length = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->length;
    p_payload->pipe   = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->pipe;
    p_payload->rssi   = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->rssi;
    p_payload->pid    = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->pid;
    p_payload->noack  = m_rx_fifo.p_payload[m_rx_fifo.exit_point]->noack; 
    memcpy(p_payload->data, m_rx_fifo.p_payload[m_rx_fifo.exit_point]->data, p_payload->length);

    if (++m_rx_fifo.exit_point >= NRF_ESB_RX_FIFO_SIZE)
    {
        m_rx_fifo.exit_point = 0;
    }

    m_rx_fifo.count--;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_start_tx(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    if (m_tx_fifo.count == 0)
    {
        return NRF_ERROR_BUFFER_EMPTY;
    }

    start_tx_transaction();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_start_rx(void)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    NRF_RADIO->INTENCLR = 0xFFFFFFFF;
    NRF_RADIO->EVENTS_DISABLED = 0;
    on_radio_disabled = on_radio_disabled_rx;

    NRF_RADIO->SHORTS      = m_radio_shorts_common | RADIO_SHORTS_DISABLED_TXEN_Msk;
    NRF_RADIO->INTENSET    = RADIO_INTENSET_DISABLED_Msk;
    m_nrf_esb_mainstate    = NRF_ESB_STATE_PRX;

    NRF_RADIO->RXADDRESSES  = m_esb_addr.rx_pipes_enabled;
    NRF_RADIO->FREQUENCY    = m_esb_addr.rf_channel;
    NRF_RADIO->PACKETPTR    = (uint32_t)m_rx_payload_buffer;

    NVIC_ClearPendingIRQ(RADIO_IRQn);
    NVIC_EnableIRQ(RADIO_IRQn);

    NRF_RADIO->EVENTS_ADDRESS = 0;
    NRF_RADIO->EVENTS_PAYLOAD = 0;
    NRF_RADIO->EVENTS_DISABLED = 0;

    NRF_RADIO->TASKS_RXEN  = 1;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_stop_rx(void)
{
    if (m_nrf_esb_mainstate == NRF_ESB_STATE_PRX)
    {
        NRF_RADIO->SHORTS = 0;
        NRF_RADIO->INTENCLR = 0xFFFFFFFF;
        on_radio_disabled = NULL;
        NRF_RADIO->EVENTS_DISABLED = 0;
        NRF_RADIO->TASKS_DISABLE = 1;
        while (NRF_RADIO->EVENTS_DISABLED == 0);
        m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;

        return NRF_SUCCESS;
    }

    return NRF_ESB_ERROR_NOT_IN_RX_MODE;
}


uint32_t nrf_esb_flush_tx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);

    DISABLE_RF_IRQ();

    m_tx_fifo.count = 0;
    m_tx_fifo.entry_point = 0;
    m_tx_fifo.exit_point = 0;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_pop_tx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
    VERIFY_TRUE(m_tx_fifo.count > 0, NRF_ERROR_BUFFER_EMPTY);

    DISABLE_RF_IRQ();

    if (++m_tx_fifo.entry_point >= NRF_ESB_TX_FIFO_SIZE)
    {
        m_tx_fifo.entry_point = 0;
    }
    m_tx_fifo.count--;

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_flush_rx(void)
{
    VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);

    DISABLE_RF_IRQ();

    m_rx_fifo.count = 0;
    m_rx_fifo.entry_point = 0;
    m_rx_fifo.exit_point = 0;

    memset(m_rx_pipe_info, 0, sizeof(m_rx_pipe_info));

    ENABLE_RF_IRQ();

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_address_length(uint8_t length)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(length > 2 && length < 6, NRF_ERROR_INVALID_PARAM);
    
    /* 
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((NRF_RADIO->BASE0 & base_address_mask) == 0 && (NRF_RADIO->PREFIX0 & 0x000000FF) == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    if((NRF_RADIO->BASE1 & base_address_mask) == 0 && ((NRF_RADIO->PREFIX0 & 0x0000FF00) == 0 ||(NRF_RADIO->PREFIX0 & 0x00FF0000) == 0 || (NRF_RADIO->PREFIX0 & 0xFF000000) == 0 ||
       (NRF_RADIO->PREFIX1 & 0xFF000000) == 0 || (NRF_RADIO->PREFIX1 & 0x00FF0000) == 0 ||(NRF_RADIO->PREFIX1 & 0x0000FF00) == 0 || (NRF_RADIO->PREFIX1 & 0x000000FF) == 0))
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    m_esb_addr.addr_length = length;

    update_rf_payload_format(m_config_local.payload_length);

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_base_address_0(uint8_t const * p_addr)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_addr);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((addr_conv(p_addr) & base_address_mask) == 0 && (NRF_RADIO->PREFIX0 & 0x000000FF) == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

    memcpy(m_esb_addr.base_addr_p0, p_addr, 4);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE0);

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_base_address_1(uint8_t const * p_addr)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_addr);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if((addr_conv(p_addr) & base_address_mask) == 0 && ((NRF_RADIO->PREFIX0 & 0x0000FF00) == 0 ||(NRF_RADIO->PREFIX0 & 0x00FF0000) == 0 || (NRF_RADIO->PREFIX0 & 0xFF000000) == 0 ||
       (NRF_RADIO->PREFIX1 & 0xFF000000) == 0 || (NRF_RADIO->PREFIX1 & 0x00FF0000) == 0 ||(NRF_RADIO->PREFIX1 & 0x0000FF00) == 0 || (NRF_RADIO->PREFIX1 & 0x000000FF) == 0))
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    memcpy(m_esb_addr.base_addr_p1, p_addr, 4);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE1);

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_prefixes(uint8_t const * p_prefixes, uint8_t num_pipes)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_PARAM_NOT_NULL(p_prefixes);
    VERIFY_TRUE(num_pipes < 9, NRF_ERROR_INVALID_PARAM);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if(num_pipes >= 1 && (NRF_RADIO->BASE0 & base_address_mask) == 0 && p_prefixes[0] == 0)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

    if((NRF_RADIO->BASE1 & base_address_mask) == 0)
    {
        for (uint8_t i = 1; i < num_pipes; i++)
        {
            if (p_prefixes[i] == 0)
            {
                return NRF_ERROR_INVALID_PARAM;
            }
        }
    }
    
    memcpy(m_esb_addr.pipe_prefixes, p_prefixes, num_pipes);
    m_esb_addr.num_pipes = num_pipes;
    m_esb_addr.rx_pipes_enabled = BIT_MASK_UINT_8(num_pipes);

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_PREFIX);

    return apply_address_workarounds();
}


uint32_t nrf_esb_update_prefix(uint8_t pipe, uint8_t prefix)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(pipe < 8, NRF_ERROR_INVALID_PARAM);
    
    /*
    Workaround for nRF52832 Rev 1 Errata 107
    Check if pipe 0 or pipe 1-7 has a 'zero address'.
    Avoid using access addresses in the following pattern (where X is don't care): 
    ADDRLEN=5 
    BASE0 = 0x0000XXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x0000XXXX, PREFIX1 = 0x00XXXXXX 

    ADDRLEN=4 
    BASE0 = 0x00XXXXXX, PREFIX0 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX0 = 0x00XXXXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXXXX00 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXXXX00XX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0xXX00XXXX 
    BASE1 = 0x00XXXXXX, PREFIX1 = 0x00XXXXXX
    */
    uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    if (pipe == 0)
    {
        if((NRF_RADIO->BASE0 & base_address_mask) == 0 && prefix == 0)
        {
            return NRF_ERROR_INVALID_PARAM;
        }
    }
    else{
        if((NRF_RADIO->BASE1 & base_address_mask) == 0 && prefix == 0)
        {
            return NRF_ERROR_INVALID_PARAM;
        }
    }
    
    m_esb_addr.pipe_prefixes[pipe] = prefix;

    update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_PREFIX);

    return apply_address_workarounds();
}


uint32_t nrf_esb_enable_pipes(uint8_t enable_mask)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_esb_addr.rx_pipes_enabled = enable_mask;

    return apply_address_workarounds();
}


uint32_t nrf_esb_set_rf_channel(uint32_t channel)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(channel <= 100, NRF_ERROR_INVALID_PARAM);

    m_esb_addr.rf_channel = channel;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_get_rf_channel(uint32_t * p_channel)
{
    VERIFY_PARAM_NOT_NULL(p_channel);

    *p_channel = m_esb_addr.rf_channel;

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_tx_power(nrf_esb_tx_power_t tx_output_power)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    if ( m_config_local.tx_output_power != tx_output_power )
    {
        m_config_local.tx_output_power = tx_output_power;
        update_radio_tx_power();
    }

    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_retransmit_delay(uint16_t delay)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(delay >= NRF_ESB_RETRANSMIT_DELAY_MIN, NRF_ERROR_INVALID_PARAM);

    m_config_local.retransmit_delay = delay;
    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_retransmit_count(uint16_t count)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_config_local.retransmit_count = count;
    return NRF_SUCCESS;
}


uint32_t nrf_esb_set_bitrate(nrf_esb_bitrate_t bitrate)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);

    m_config_local.bitrate = bitrate;
    return update_radio_bitrate() ? NRF_SUCCESS : NRF_ERROR_INVALID_PARAM;
}


uint32_t nrf_esb_reuse_pid(uint8_t pipe)
{
    VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
    VERIFY_TRUE(pipe < 8, NRF_ERROR_INVALID_PARAM);

    m_pids[pipe] = (m_pids[pipe] + NRF_ESB_PID_MAX) % (NRF_ESB_PID_MAX + 1);
    return NRF_SUCCESS;
}


// Handler for 
#ifdef NRF52
void NRF_ESB_BUGFIX_TIMER_IRQHandler(void)
{
    if(NRF_ESB_BUGFIX_TIMER->EVENTS_COMPARE[0])
    {
        NRF_ESB_BUGFIX_TIMER->EVENTS_COMPARE[0] = 0;

        // If the timeout timer fires and we are in the PTX receive ACK state, disable the radio
        if(m_nrf_esb_mainstate == NRF_ESB_STATE_PTX_RX_ACK)
        {
            NRF_RADIO->TASKS_DISABLE = 1;
        }
    }
}
#endif