How to use the CONFIG_ESB_NEVER_DISABLE_TX?

Hi all,

I want to reduce delay in sending or receiving data via ESB.

And now I use the fast ramp-up. In this link said Never disable transmission stage can do this too, but I didn't find anything about this macro.

How do I enable this function?

nRF52832, SDK 17.1.0 

Best regards,

Lurn

  • Hi lurn,

    The Never disable transmission stage that you mentioned is a feature for the nRF Connect SDK whereas you are using thenRF 5 SDK, so it is not possible to have this feature there.. You could maybe use the nrf_esb_set_retransmit_delay() function to set the delay.? 

    Regards,

    Swathy

  • Hi Swathy,

    I think this function didn't fit my case, the nrf_esb_set_retransmit_delay() is set the retransmit delay time. But what I want is to reduce the delay between TX FIFO filling and reception to minimum.

    Best regards

    Lurn

  • Hi Lurn,

    I will check with experts when it comes to ESB and get back to you. However, please expect a delay since we are a bit short staffed owing to the vacation season here (The said experts are away on holidays as well).

    Regards,

    Swathy

  • Hi Swathy,

    OK, Thanks, I will wait for you.

    Best regards,

    Lurn

  • Hi Lurn,

    The features that you mentioned is for nRF Connect SDK, but it would be possible to make changes to the nRF 5 SDK ESB library to incorporate these features into it as well. However, since the nRF 5 SDK is now in maintenance mode, there won't be anymore updates to the already existing package. You will need to make these changes yourself though.. An expert has made changes to the nrf 5 SDK ESB library to include fast rampup and am attaching it here. Please note that this has not been tested. 'Never disable transmission stage' can also be implemented the same way but would be more work since the ESB library assumes thatthe radio will be disabled for every recievd and sent libary.

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     *
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     * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
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     * 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_delay.h"
    
    #define BIT_MASK_UINT_8(x) (0xFF >> (8 - (x)))
    
    // 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        (73)        /**< 1 Mb RX wait for acknowledgment time-out value. Smallest reliable value - 68. */
    #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.*/
    #define RETRANSMIT_DELAY_US_OFFSET              (62)        /**< Never retransmit before the wait for ack time plus this offset. */
    
    // 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. */
    } pipe_info_t;
    
    
    /* @brief Structure used by the PRX to organize ACK payloads for multiple pipes. */ 
    typedef struct
    {
        nrf_esb_payload_t * p_payload;                        /**< Pointer to the ACK payload. */
        bool                in_use;                           /**< Value used to determine if the current payload pointer is used. */
        struct nrf_esb_payload_random_access_buf_wrapper_t * p_next; /**< Pointer to the next ACK payload queued on the same pipe. */
    } nrf_esb_payload_random_access_buf_wrapper_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 volatile 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 + 2];
    static  uint8_t                     m_rx_payload_buffer[NRF_ESB_MAX_PAYLOAD_LENGTH + 2];
    
    // Random access buffer variables for better ACK payload handling
    nrf_esb_payload_random_access_buf_wrapper_t m_ack_pl_container[NRF_ESB_TX_FIFO_SIZE];
    nrf_esb_payload_random_access_buf_wrapper_t * m_ack_pl_container_entry_point_pr_pipe[NRF_ESB_PIPE_COUNT];
    
    // 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;
    
    static volatile 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)
    {
    #if __CORTEX_M == (0x04U)
        uint32_t inp = (*(uint32_t*)p_inp);
        return __REV((uint32_t)__RBIT(inp)); //lint -esym(628, __rev) -esym(526, __rev) -esym(628, __rbit) -esym(526, __rbit) */
    #else
        uint32_t inp = (p_inp[3] << 24) | (p_inp[2] << 16) | (p_inp[1] << 8) | (p_inp[0]);
        inp = (inp & 0xF0F0F0F0) >> 4 | (inp & 0x0F0F0F0F) << 4;
        inp = (inp & 0xCCCCCCCC) >> 2 | (inp & 0x33333333) << 2;
        inp = (inp & 0xAAAAAAAA) >> 1 | (inp & 0x55555555) << 1;
        return inp;
    #endif
    }
    
    
    // Convert a base address from nRF24L format to nRF5 format
    static uint32_t addr_conv(uint8_t const* p_addr)
    {
        return __REV(bytewise_bit_swap(p_addr)); //lint -esym(628, __rev) -esym(526, __rev) */
    }
    
    #ifdef NRF52832_XXAA
    static ret_code_t apply_address_workarounds()
    {
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200) //Check if the device is an nRF52832 Rev. 1.
        {
            // Workaround for nRF52832 Rev 1 erratas
            //  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;
        }
    
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004500)//Check if the device is an nRF52832 Rev. 2.
        {
            /*
            Workaround for nRF52832 Rev 2 Errata 143
            Check if the most significant bytes of address 0 (including prefix) match those of another address.
            It's recommended to use a unique address 0 since this will avoid the 3dBm penalty incurred from the workaround.
            */
            uint32_t base_address_mask = m_esb_addr.addr_length == 5 ? 0xFFFF0000 : 0xFF000000;
    
            // Load the two addresses before comparing them to ensure defined ordering of volatile accesses.
            uint32_t addr0 = NRF_RADIO->BASE0 & base_address_mask;
            uint32_t addr1 = NRF_RADIO->BASE1 & base_address_mask;
            if (addr0 == addr1)
            {
                uint32_t prefix0 = NRF_RADIO->PREFIX0 & 0x000000FF;
                uint32_t prefix1 = (NRF_RADIO->PREFIX0 & 0x0000FF00) >> 8;
                uint32_t prefix2 = (NRF_RADIO->PREFIX0 & 0x00FF0000) >> 16;
                uint32_t prefix3 = (NRF_RADIO->PREFIX0 & 0xFF000000) >> 24;
                uint32_t prefix4 = NRF_RADIO->PREFIX1 & 0x000000FF;
                uint32_t prefix5 = (NRF_RADIO->PREFIX1 & 0x0000FF00) >> 8;
                uint32_t prefix6 = (NRF_RADIO->PREFIX1 & 0x00FF0000) >> 16;
                uint32_t prefix7 = (NRF_RADIO->PREFIX1 & 0xFF000000) >> 24;
    
                if (prefix0 == prefix1 || prefix0 == prefix2 || prefix0 == prefix3 || prefix0 == prefix4 ||
                    prefix0 == prefix5 || prefix0 == prefix6 || prefix0 == prefix7)
                {
                    // This will cause a 3dBm sensitivity loss, avoid using such address combinations if possible.
                    *(volatile uint32_t *) 0x40001774 = ((*(volatile uint32_t *) 0x40001774) & 0xfffffffe) | 0x01000000;
                }
            }
        }
        return NRF_SUCCESS;
    }
    #endif
    
    
    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 = (0 << RADIO_PCNF0_S0LEN_Pos) |
                           (6 << RADIO_PCNF0_LFLEN_Pos) |
                           (3 << RADIO_PCNF0_S1LEN_Pos) ;
    #else
        // Using 8 bits for length
        NRF_RADIO->PCNF0 = (0 << RADIO_PCNF0_S0LEN_Pos) |
                           (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_Big          << 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_Big          << 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 RADIO_MODE_MODE_Ble_2Mbit
            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 RADIO_MODE_MODE_Nrf_250Kbit
            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;
        }
    
        // Ensure that we do not attempt retransmitting before ack timeout.
        if (m_config_local.retransmit_delay < m_wait_for_ack_timeout_us + RETRANSMIT_DELAY_US_OFFSET)
        {
            m_config_local.retransmit_delay = m_wait_for_ack_timeout_us + RETRANSMIT_DELAY_US_OFFSET;
        }
    
        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:
                NRF_RADIO->CRCINIT = 0x00UL;
                NRF_RADIO->CRCPOLY = 0x00UL;
                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);
        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];
        }
        
        for (int i = 0; i < NRF_ESB_TX_FIFO_SIZE; i++)
        {
            m_ack_pl_container[i].p_payload = &m_tx_fifo_payload[i];
            m_ack_pl_container[i].in_use = false;
            m_ack_pl_container[i].p_next = 0;
        }
        for (int i = 0; i < NRF_ESB_PIPE_COUNT; i++)
        {
            m_ack_pl_container_entry_point_pr_pipe[i] = 0;
        }
    }
    
    
    uint32_t nrf_esb_skip_tx()
    {
        VERIFY_TRUE(m_esb_initialized, NRF_ERROR_INVALID_STATE);
        VERIFY_TRUE(m_tx_fifo.count > 0, NRF_ERROR_BUFFER_EMPTY);
    
        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();
    
        return NRF_SUCCESS;
    }
    
    /** @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[0] > NRF_ESB_MAX_PAYLOAD_LENGTH)
                {
                    return false;
                }
    
                m_rx_fifo.p_payload[m_rx_fifo.entry_point]->length = m_rx_payload_buffer[0];
            }
            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[2],
                   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[1] & 0x01);
            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_SHUTDOWN;
    
        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:
                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] = mp_current_payload->length;
                m_tx_payload_buffer[1] = mp_current_payload->pid << 1;
                m_tx_payload_buffer[1] |= mp_current_payload->noack ? 0x00 : 0x01;
                memcpy(&m_tx_payload_buffer[2], mp_current_payload->data, mp_current_payload->length);
    
                // 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;
        (void) nrf_esb_skip_tx();
    
        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 - 40;
        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_SHUTDOWN = 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;
    
            (void) nrf_esb_skip_tx();
    
            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_SHUTDOWN = 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[1] >> 1) == p_pipe_info->pid
           )
        {
            retransmit_payload = true;
            send_rx_event = false;
        }
    
        p_pipe_info->pid = m_rx_payload_buffer[1] >> 1;
        p_pipe_info->crc = NRF_RADIO->RXCRC;
    
        if ((m_config_local.selective_auto_ack == false) || ((m_rx_payload_buffer[1] & 0x01) == 1))
        {
            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_ack_pl_container_entry_point_pr_pipe[NRF_RADIO->RXMATCH] != 0)
                        {
                            mp_current_payload = m_ack_pl_container_entry_point_pr_pipe[NRF_RADIO->RXMATCH]->p_payload;
    
                            // 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)
                            {
                                uint32_t pipe = NRF_RADIO->RXMATCH;
                                m_ack_pl_container_entry_point_pr_pipe[pipe]->in_use = false;
                                m_ack_pl_container_entry_point_pr_pipe[pipe] = (nrf_esb_payload_random_access_buf_wrapper_t *)m_ack_pl_container_entry_point_pr_pipe[pipe]->p_next;
                                m_tx_fifo.count--;
                                if (m_tx_fifo.count > 0 && m_ack_pl_container_entry_point_pr_pipe[pipe] != 0)
                                {
                                     mp_current_payload = m_ack_pl_container_entry_point_pr_pipe[pipe]->p_payload;
                                }
                                else mp_current_payload = 0;
    
                                // 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;
                            }
    
                            if(mp_current_payload != 0)
                            {
                                p_pipe_info->ack_payload = true;
                                update_rf_payload_format(mp_current_payload->length);
                                m_tx_payload_buffer[0] = mp_current_payload->length;
                                memcpy(&m_tx_payload_buffer[2],
                                       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] = 0;
                            }
                        }
                        else
                        {
                            p_pipe_info->ack_payload = false;
                            update_rf_payload_format(0);
                            m_tx_payload_buffer[0] = 0;
                        }
    
                        m_tx_payload_buffer[1] = m_rx_payload_buffer[1];
                    }
                    break;
    
                case NRF_ESB_PROTOCOL_ESB:
                    {
                        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();
    
        NRF_RADIO->MODECNF0 = (NRF_RADIO->MODECNF0 & ~RADIO_MODECNF0_RU_Pos) | RADIO_MODECNF0_RU_Fast << RADIO_MODECNF0_RU_Pos;
    
        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);
    
        m_nrf_esb_mainstate = NRF_ESB_STATE_IDLE;
        m_esb_initialized = true;
    
    
    #ifdef NRF52832_XXAA
    if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004500) //Check if the device is an nRF52832 Rev. 2.
        //Workaround for nRF52832 rev 2 errata 182
        *(volatile uint32_t *) 0x4000173C |= (1 << 10);
    #endif
    
        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;
        m_esb_initialized = false;
    
        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);
            }
        }
    }
    
    
    static nrf_esb_payload_random_access_buf_wrapper_t *find_free_payload_cont(void)
    {
        for (int i = 0; i < NRF_ESB_TX_FIFO_SIZE; i++)
        {
            if(!m_ack_pl_container[i].in_use) return &m_ack_pl_container[i];
        }
        return 0;
    }
    
    
    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();
    
        if (m_config_local.mode == NRF_ESB_MODE_PTX)
        {
            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++;
        }
        else
        {
            nrf_esb_payload_random_access_buf_wrapper_t *new_ack_payload;
            if((new_ack_payload = find_free_payload_cont()) != 0)
            {
                new_ack_payload->in_use = true;
                new_ack_payload->p_next = 0;
                memcpy(new_ack_payload->p_payload, p_payload, sizeof(nrf_esb_payload_t));
    
                m_pids[p_payload->pipe] = (m_pids[p_payload->pipe] + 1) % (NRF_ESB_PID_MAX + 1);
                new_ack_payload->p_payload->pid = m_pids[p_payload->pipe];
    
                if(m_ack_pl_container_entry_point_pr_pipe[p_payload->pipe] == 0)
                {
                    m_ack_pl_container_entry_point_pr_pipe[p_payload->pipe] = new_ack_payload;
                }
                else
                {
                    nrf_esb_payload_random_access_buf_wrapper_t *list_iterator = m_ack_pl_container_entry_point_pr_pipe[p_payload->pipe];
                    while(list_iterator->p_next != 0)
                    {
                        list_iterator = (nrf_esb_payload_random_access_buf_wrapper_t *)list_iterator->p_next;
                    }
                    list_iterator->p_next = (struct nrf_esb_payload_random_access_buf_wrapper_t *)new_ack_payload;
                }
                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 ||
            m_nrf_esb_mainstate == NRF_ESB_STATE_PRX_SEND_ACK)
        {
            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 == 0)
        {
            m_tx_fifo.entry_point = (NRF_ESB_TX_FIFO_SIZE-1);
        }
        else
        {
            m_tx_fifo.entry_point--;
        }
        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);
    
    #ifdef NRF52832_XXAA
        uint32_t base_address_mask = length == 5 ? 0xFFFF0000 : 0xFF000000;
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200)  //Check if the device is an nRF52832 Rev. 1.
        {
            /*
            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
            */
            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;
            }
        }
    #endif
    
        m_esb_addr.addr_length = length;
    
        update_rf_payload_format(m_config_local.payload_length);
    
    #ifdef NRF52832_XXAA
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004500)  //Check if the device is an nRF52832 Rev. 2.
        {
            return apply_address_workarounds();
        }
        else
        {
            return NRF_SUCCESS;
        }
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    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);
    
    #ifdef NRF52832_XXAA
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200)  //Check if the device is an nRF52832 Rev. 1.
        {
            /*
            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;
            }
        }
    #endif
    
    
    
        memcpy(m_esb_addr.base_addr_p0, p_addr, 4);
    
        update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE0);
    #ifdef NRF52832_XXAA
        return apply_address_workarounds();
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    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);
    
    #ifdef NRF52832_XXAA
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200)  //Check if the device is an nRF52832 Rev. 1.
        {
            /*
            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;
            }
        }
    #endif
    
        memcpy(m_esb_addr.base_addr_p1, p_addr, 4);
    
        update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_BASE1);
    
    #ifdef NRF52832_XXAA
        return apply_address_workarounds();
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    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 <= NRF_ESB_PIPE_COUNT, NRF_ERROR_INVALID_PARAM);
    
    #ifdef NRF52832_XXAA
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200)  //Check if the device is an nRF52832 Rev. 1.
        {
            /*
            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;
                    }
                }
            }
        }
    #endif
    
        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);
    
    #ifdef NRF52832_XXAA
        return apply_address_workarounds();
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    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 < NRF_ESB_PIPE_COUNT, NRF_ERROR_INVALID_PARAM);
    
    #ifdef NRF52832_XXAA
        if ((NRF_FICR->INFO.VARIANT & 0x0000FF00) == 0x00004200)  //Check if the device is an nRF52832 Rev. 1.
        {
            /*
            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;
                }
            }
        }
    #endif
        m_esb_addr.pipe_prefixes[pipe] = prefix;
    
        update_radio_addresses(NRF_ESB_ADDR_UPDATE_MASK_PREFIX);
    
    #ifdef NRF52832_XXAA
        return apply_address_workarounds();
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    uint32_t nrf_esb_enable_pipes(uint8_t enable_mask)
    {
        VERIFY_TRUE(m_nrf_esb_mainstate == NRF_ESB_STATE_IDLE, NRF_ERROR_BUSY);
        VERIFY_TRUE((enable_mask | BIT_MASK_UINT_8(NRF_ESB_PIPE_COUNT)) == BIT_MASK_UINT_8(NRF_ESB_PIPE_COUNT), NRF_ERROR_INVALID_PARAM);
    
        m_esb_addr.rx_pipes_enabled = enable_mask;
    
    #ifdef NRF52832_XXAA
        return apply_address_workarounds();
    #else
        return NRF_SUCCESS;
    #endif
    }
    
    
    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 >= m_wait_for_ack_timeout_us + RETRANSMIT_DELAY_US_OFFSET, 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 < NRF_ESB_PIPE_COUNT, NRF_ERROR_INVALID_PARAM);
    
        m_pids[pipe] = (m_pids[pipe] + NRF_ESB_PID_MAX) % (NRF_ESB_PID_MAX + 1);
        return NRF_SUCCESS;
    }
    
    
    #ifdef NRF52832_XXAA
    // Workaround neccessary on nRF52832 Rev. 1.
    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
    

    Best Regards,

    Swathy

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