sd_ble_gatts_hvx gives error as NRF_ERROR_RESOURCES and my code gets stuck

[Mushtakh Shaikh]

Fullscreen 3060.nrf_data_send_over_ble_issues.txt Download

uint32_t ble_cus_sensor_state_update(ble_cus_t * p_cus, int8_t  * p_buttons_states, int length, uint16_t conn_handle)
{
    ble_gatts_hvx_params_t params;
    uint16_t len = length;
    uint32_t err_code;

    memset(&params, 0, sizeof(params));
    params.type   = BLE_GATT_HVX_NOTIFICATION;//BLE_GATT_HVX_NOTIFICATION;
    params.handle = p_cus->leds_states_char_handles.value_handle;
    params.p_data = p_buttons_states;
    params.p_len  = &len;

    return sd_ble_gatts_hvx(conn_handle, &params);
}



void ble_cus_send_sensor_data(uint8_t *data, uint16_t len)
{
      ret_code_t err_code;
      uint32_t timer = millis();
      do{
        err_code = ble_cus_sensor_state_update(&m_cus, data, len, m_conn_handle);
      }while(err_code == BLE_ERROR_GATTS_SYS_ATTR_MISSING && millis() - timer < 3000 && (err_code == NRF_ERROR_RESOURCES));
      if ( err_code != NRF_SUCCESS                   &&
           err_code != BLE_ERROR_INVALID_CONN_HANDLE &&
           err_code != NRF_ERROR_INVALID_STATE       &&
        /*   (err_code != NRF_ERROR_RESOURCES)         &&*/
           err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)
      {

        APP_ERROR_CHECK(err_code);
      }
}

void send_current_data(void)
{
	printf("Sending current data \n");
	for(int i=0;i<500;i++)
	{
		memset(lv_data_header,0,sizeof(lv_data_header));
		lv_data_header[0] =0xFF;
		lv_data_header[0] =i;
		ble_cus_send_sensor_data(lv_data_header, 2); 
		if( m_ble_cust_packet_sent == true)
		{
			printf("Sending current data packet %d  \n",i);
			ble_cus_send_sensor_data(lv_data_header, 2); 
		}
	}
}


void cus_evt_handler(ble_cus_t * p_cus, ble_cus_evt_t * p_evt)
{ 
   uint8_t u8_cmd_id = 0;

  switch(p_evt->evt_type)
  {
    case BLE_LEDS_STATES_CHAR_EVT_COMMAND_RX:
    {
        if(p_evt->params_command.command_data.p_data[0] == 0XFD)
		{
			send_current_data();
		}
        

	}
}

Hi Nordic team

Currently I am trying to send a big chunk of data close to 100 KB from my nRF52832 to nRF connect for mobile app in Android phone. I am able to send few bytes in one shot. But when I kept a loop for sending more than 10 data packets, my code is getting stuck in while loop and sd_ble_gatts_hvx  returns NRF_ERROR_RESOURCES error. After that my application is stuck until I restart the application. It is not accepting any new command and stops sending the data. 

I already change hvn_tx_queue_size = 20 and NRF_SDH_BLE_GAP_EVENT_LENGTH to 20 even to larger number , but still it doesn't resolve the issue.

Also it is blocking BLE_GATTS_EVT_HVN_TX_COMPLETE event handler. So I am unable to understand if the queue buffer resource is empty or not.

[Edvin]

Hello,

I believe you are waiting in an interrupt with equal or higher priority than the BLE_GATTS_EVT_HVN_TX_COMPLETE event (ble_evt_handler()).

In fact, I suspect that the interrupt you are waiting in is the ble_evt_handler(), or the equivalent handler that you registered for your custom service handler. As long as you are not leaving the interrupt, the BLE_GATTS_EVT_HVN_TX_COMPLETE event will not be able to execute, to tell your application that the softdevice has freed up some buffers.

So one way to handle this is to keep track of what you have queued successfully. So you need to queue up as much as you can, until your ble_cus_sensor_state_update() returns NRF_ERROR_RESOURCES. When it does, keep track of how much data you queued in your send_current_data(), and return from this function, so that the interrupt is released. Then you can wait for the BLE_GATTS_EVT_HVN_TX_COMPLETE event, which means that at least one of your packets was acked. Then you can set a flag in the TX_COMPLETE callback, that you can check in your main-loop, and use this to continue where you left off, queuing more packets, until it returns NRF_ERROR_RESOURCES again, or you have successfully queued all your packets. 

Something like this:

volatile uint32_t packet_counter = 0;
volatile bool send_data_flag = false;

ble_evt_handler()
{
    ...
    case BLE_GATTS_EVT_HVN_TX_COMPLETE:
        if ( **check if more data needs to be sent**)
        {
            send_data_flag = true;
        }
}

send_data()
{
    for (int i=0; i<100; i++)
    {
        err = NRF_SUCCESS;
        while(err = NRF_SUCCESS)
        {
            sd_ble_gatts_hvx(...);
            if (err = NRF_SUCCESS)
            {
                packet_counter = i;
                i++;
            }
        }
        break;
    }
}
cust_data_handler()
{
    send_data_flag = true;
}

int main()
{
...
    while (true)
    {
        if (send_data_flag)
        {
            send_data_flag = false;
            send_data();
        }
        idle_state_handle();
    }
}

Best regards,

Edvin

[Mushtakh Shaikh]

Fullscreen 4861.main.c Download

/**
 * Copyright (c) 2014 - 2021, 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.
 *
 */
/** @file
 *
 * @defgroup ble_sdk_uart_over_ble_main main.c
 * @{
 * @ingroup  ble_sdk_app_nus_eval
 * @brief    UART over BLE application main file.
 *
 * This file contains the source code for a sample application that uses the Nordic UART service.
 * This application uses the @ref srvlib_conn_params module.
 */

#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"

#include "nrf_dfu_ble_svci_bond_sharing.h"
#include "nrf_svci_async_function.h"
#include "nrf_svci_async_handler.h"

#include "app_timer.h"
#include "nrf_drv_wdt.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "bsp_btn_ble.h"
#include "nrf_pwr_mgmt.h"
#include "nrf_drv_twi.h"

#include "nrf_delay.h"
#include "nrf_gpio.h"
#include "boards.h"

#include "ble_dfu.h"
#include "fds.h"
#include "nrf_bootloader_info.h"
#include "nrf_drv_rtc.h"
#include "nrf_drv_clock.h"
#include "nrf_power.h"

#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "ble_protocol_handle.h"
#include "nrf_flash_app.h"
#include "ble_cus.h"
#include "adc_vbat_read.h"
#include "app_pwm.h"
#include "sensor_mode.h"
#include "ble_dis.h"
#include "app_flash_data_storage.h"
#define APP_TIMER_PRESCALER             0                                           /**< Value of the RTC1 PRESCALER register. */
#define ADC_CHANNEL                     1
#define APP_BLE_CONN_CFG_TAG            1                                           /**< A tag identifying the SoftDevice BLE configuration. */

#define DEVICE_NAME                     "Sensor_Demo"                               /**< Name of device. Will be included in the advertising data. */
#define NUS_SERVICE_UUID_TYPE           BLE_UUID_TYPE_VENDOR_BEGIN                  /**< UUID type for the Nordic UART Service (vendor specific). */

#define BATTERY_LEVEL_MEAS_INTERVAL_5_MIN        APP_TIMER_TICKS(100)   //5 minutes   /**< Battery level measurement interval (ticks). This value corresponds to 60 minutes. */
#define APP_BLE_OBSERVER_PRIO           3                                           /**< Application's BLE observer priority. You shouldn't need to modify this value. */

#define APP_ADV_INTERVAL                64                                                                               /**< The advertising interval (in units of 0.625 ms. This value corresponds to 40 ms). */

#define APP_ADV_DURATION                0                                    /* No timeout ; continous advertising */                                       /**< The advertising duration (180 seconds) in units of 10 milliseconds. */

#define MIN_CONN_INTERVAL               MSEC_TO_UNITS(100, UNIT_1_25_MS)        /**< Minimum acceptable connection interval (0.5 seconds). */
#define MAX_CONN_INTERVAL               MSEC_TO_UNITS(200, UNIT_1_25_MS)             /**< Maximum acceptable connection interval (75 ms), Connection interval uses 1.25 ms units. */
#define SLAVE_LATENCY                   4                                           /**< Slave latency. */
#define CONN_SUP_TIMEOUT                MSEC_TO_UNITS(4000, UNIT_10_MS)             /**< Connection supervisory timeout (4 seconds), Supervision Timeout uses 10 ms units. */
#define FIRST_CONN_PARAMS_UPDATE_DELAY  APP_TIMER_TICKS(5000)  /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(30000) /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT    3                                           /**< Number of attempts before giving up the connection parameter negotiation. */

#define DEAD_BEEF                       0xDEADBEEF                                  /**< Value used as error code on stack dump, can be used to identify stack location on stack unwind. */

#define FPU_EXCEPTION_MASK              0x0000009F

#define UART_TX_BUF_SIZE                256                                         /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE                256                                         /**< UART RX buffer size. */

#define CURRENT_DATA                    0XFF
#define SEND_CURRENT_DATA               0XFF
#define APP_TIMER_PRESCALER             0  

int gv_alert_freq_count = 1;
#define ALERT_PACKET                    25
extern int8_t sensor_alert_packet[ALERT_PACKET];                                         /**< Value of the RTC1 PRESCALER register. */
/**@brief Macro to convert the result of ADC conversion in millivolts.
 *
 * @param[in]  ADC_VALUE   ADC result.
 *
 * @retval     Result converted to millivolts.
 */

// Create a handle that will point to the RTC 2 of nrf device
const nrfx_rtc_t rtc = NRFX_RTC_INSTANCE(2); // rtc 2 handle

//BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);                                   /**< BLE NUS service instance. */
NRF_BLE_GATT_DEF(m_gatt);                                                           /**< GATT module instance. */
NRF_BLE_QWR_DEF(m_qwr);   
BLE_CUS_DEF(m_cus);                                                                                                                           /**< Battery service instance. */                                                          /**< Context for the Queued Write module.*/
BLE_ADVERTISING_DEF(m_advertising);
                                                 /**< Advertising module instance. */
APP_TIMER_DEF(m_repeated_timer_id0);         
APP_TIMER_DEF(m_repeated_timer_id1);  
APP_TIMER_DEF(m_repeated_timer_id2);   
APP_TIMER_DEF(m_repeated_timer_id3);

nrf_drv_wdt_channel_id m_channel_id;

extern uint8_t tx_complete_flag;
extern uint8_t gv_date_time_command;
static uint16_t   m_conn_handle          = BLE_CONN_HANDLE_INVALID;                 /**< Handle of the current connection. */
static uint16_t   m_ble_nus_max_data_len = BLE_GATT_ATT_MTU_DEFAULT - 3;            /**< Maximum length of data (in bytes) that can be transmitted to the peer by the Nordic UART service module. */

static ble_uuid_t m_adv_uuids[] =                                               /**< Universally unique service identifiers. */
{
    {BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE}
};






/**@brief Handler for shutdown preparation.
 *
 * @details During shutdown procedures, this function will be called at a 1 second interval
 *          untill the function returns true. When the function returns true, it means that the
 *          app is ready to reset to DFU mode.
 *
 * @param[in]   event   Power manager event.
 *
 * @retval  True if shutdown is allowed by this power manager handler, otherwise false.
 */
static bool app_shutdown_handler(nrf_pwr_mgmt_evt_t event)
{
    switch (event)
    {
        case NRF_PWR_MGMT_EVT_PREPARE_DFU:
            NRF_LOG_INFO("Power management wants to reset to DFU mode.");
            // YOUR_JOB: Get ready to reset into DFU mode
            //
            // If you aren't finished with any ongoing tasks, return "false" to
            // signal to the system that reset is impossible at this stage.
            //
            // Here is an example using a variable to delay resetting the device.
            //
            // if (!m_ready_for_reset)
            // {
            //      return false;
            // }
            // else
            //{
            //
            //    // Device ready to enter
            //    uint32_t err_code;
            //    err_code = sd_softdevice_disable();
            //    APP_ERROR_CHECK(err_code);
            //    err_code = app_timer_stop_all();
            //    APP_ERROR_CHECK(err_code);
            //}
            break;

        default:
            // YOUR_JOB: Implement any of the other events available from the power management module:
            //      -NRF_PWR_MGMT_EVT_PREPARE_SYSOFF
            //      -NRF_PWR_MGMT_EVT_PREPARE_WAKEUP
            //      -NRF_PWR_MGMT_EVT_PREPARE_RESET
            return true;
    }

    NRF_LOG_INFO("Power management allowed to reset to DFU mode.");
    return true;
}

//lint -esym(528, m_app_shutdown_handler)
/**@brief Register application shutdown handler with priority 0.
 */
NRF_PWR_MGMT_HANDLER_REGISTER(app_shutdown_handler, 0);


static void buttonless_dfu_sdh_state_observer(nrf_sdh_state_evt_t state, void * p_context)
{
    if (state == NRF_SDH_EVT_STATE_DISABLED)
    {
        // Softdevice was disabled before going into reset. Inform bootloader to skip CRC on next boot.
        nrf_power_gpregret2_set(BOOTLOADER_DFU_SKIP_CRC);

        //Go to system off.
        nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);
    }
}

/* nrf_sdh state observer. */
NRF_SDH_STATE_OBSERVER(m_buttonless_dfu_state_obs, 0) =
{
    .handler = buttonless_dfu_sdh_state_observer,
};


static void advertising_config_get(ble_adv_modes_config_t * p_config)
{
    memset(p_config, 0, sizeof(ble_adv_modes_config_t));

    p_config->ble_adv_fast_enabled  = true;
    p_config->ble_adv_fast_interval = APP_ADV_INTERVAL;
    p_config->ble_adv_fast_timeout  = APP_ADV_DURATION;
}


static void disconnect(uint16_t conn_handle, void * p_context)
{
    UNUSED_PARAMETER(p_context);

    ret_code_t err_code = sd_ble_gap_disconnect(conn_handle, BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
    if (err_code != NRF_SUCCESS)
    {
        NRF_LOG_WARNING("Failed to disconnect connection. Connection handle: %d Error: %d", conn_handle, err_code);
    }
    else
    {
        NRF_LOG_DEBUG("Disconnected connection handle %d", conn_handle);
    }
}
// YOUR_JOB: Update this code if you want to do anything given a DFU event (optional).
/**@brief Function for handling dfu events from the Buttonless Secure DFU service
 *
 * @param[in]   event   Event from the Buttonless Secure DFU service.
 */
static void ble_dfu_evt_handler(ble_dfu_buttonless_evt_type_t event)
{
    switch (event)
    {
        case BLE_DFU_EVT_BOOTLOADER_ENTER_PREPARE:
        {
            NRF_LOG_INFO("Device is preparing to enter bootloader mode.");

            // Prevent device from advertising on disconnect.
            ble_adv_modes_config_t config;
            advertising_config_get(&config);
            config.ble_adv_on_disconnect_disabled = true;
            ble_advertising_modes_config_set(&m_advertising, &config);

            // Disconnect all other bonded devices that currently are connected.
            // This is required to receive a service changed indication
            // on bootup after a successful (or aborted) Device Firmware Update.
            uint32_t conn_count = ble_conn_state_for_each_connected(disconnect, NULL);
            NRF_LOG_INFO("Disconnected %d links.", conn_count);
            break;
        }

        case BLE_DFU_EVT_BOOTLOADER_ENTER:
            // YOUR_JOB: Write app-specific unwritten data to FLASH, control finalization of this
            //           by delaying reset by reporting false in app_shutdown_handler
            NRF_LOG_INFO("Device will enter bootloader mode.");
            break;
        case BLE_DFU_EVT_BOOTLOADER_ENTER_FAILED:
            NRF_LOG_ERROR("Request to enter bootloader mode failed asynchroneously.");
            // YOUR_JOB: Take corrective measures to resolve the issue
            //           like calling APP_ERROR_CHECK to reset the device.
            break;

        case BLE_DFU_EVT_RESPONSE_SEND_ERROR:
            NRF_LOG_ERROR("Request to send a response to client failed.");
            // YOUR_JOB: Take corrective measures to resolve the issue
            //           like calling APP_ERROR_CHECK to reset the device.
            APP_ERROR_CHECK(false);
            break;

        default:
            NRF_LOG_ERROR("Unknown event from ble_dfu_buttonless.");
            break;
    }
}

/**@brief Function for initializing the timer module.
*/
void timers_init(void)
{
    lfclk_config();
    // Initialize timer module, making it use the scheduler
    ret_code_t err_code = app_timer_init();
    APP_ERROR_CHECK(err_code);
    
    err_code = app_timer_create(&m_repeated_timer_id0,
                                APP_TIMER_MODE_REPEATED,
                                repeated_timer_handler);
    APP_ERROR_CHECK(err_code);

    err_code = app_timer_create(&m_repeated_timer_id1,
                                APP_TIMER_MODE_REPEATED,
                                repeated_timer_handler);
    APP_ERROR_CHECK(err_code);
    err_code = app_timer_create(&m_repeated_timer_id2,
                                APP_TIMER_MODE_REPEATED,
                                high_performance_timer_handler);
    APP_ERROR_CHECK(err_code);

    err_code = app_timer_create(&m_repeated_timer_id3,
                                APP_TIMER_MODE_REPEATED,
                                watchdog_timer_handle);
    APP_ERROR_CHECK(err_code);
}
void application_timers_start(void){
    ret_code_t err_code = 0;
    uint8_t sensor_mode = get_sensor_mode();
    if(sensor_mode == ULTRA_LOW_POWER_MODE){
      err_code = app_timer_start(m_repeated_timer_id0, APP_TIMER_TICKS(300000), NULL);
    }
    else if(sensor_mode == LOW_POWER_MODE){
      err_code = app_timer_start(m_repeated_timer_id1, APP_TIMER_TICKS(10000), NULL);
    }
    else if(sensor_mode == HIGH_PERFORMANCE_MODE){
      err_code = app_timer_start(m_repeated_timer_id2, APP_TIMER_TICKS(50), NULL);
    }
    APP_ERROR_CHECK(err_code);
    err_code = app_timer_start(m_repeated_timer_id3, APP_TIMER_TICKS(1000), NULL);
    APP_ERROR_CHECK(err_code);
}




/**@brief Function for the GAP initialization.
 *
 * @details This function will set up all the necessary GAP (Generic Access Profile) parameters of
 *          the device. It also sets the permissions and appearance.
 */
static void gap_params_init(void)
{
    uint32_t                err_code;
    ble_gap_conn_params_t   gap_conn_params;
    ble_gap_conn_sec_mode_t sec_mode;
  
    ble_gap_addr_t   device_addr;
    uint8_t          tmp_local_name[30];
    uint8_t          tmp_len;

    BLE_GAP_CONN_SEC_MODE_SET_OPEN(&sec_mode);

    // Get BLE address.
    err_code = sd_ble_gap_addr_get(&device_addr);
    APP_ERROR_CHECK(err_code);

    strcpy(tmp_local_name, DEVICE_NAME);

    tmp_len = strlen(tmp_local_name);
    snprintf(&tmp_local_name[tmp_len], 30-tmp_len, "_%02x", device_addr.addr[0]);
    //printf("Advertising started with Local Name %s\r\n",tmp_local_name);

    err_code = sd_ble_gap_device_name_set(&sec_mode,
                                          (const uint8_t *) tmp_local_name,
                                          strlen(tmp_local_name));
    APP_ERROR_CHECK(err_code);

    memset(&gap_conn_params, 0, sizeof(gap_conn_params));

    gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
    gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
    gap_conn_params.slave_latency     = SLAVE_LATENCY;
    gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;

    err_code = sd_ble_gap_ppcp_set(&gap_conn_params);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling Queued Write Module errors.
 *
 * @details A pointer to this function will be passed to each service which may need to inform the
 *          application about an error.
 *
 * @param[in]   nrf_error   Error code containing information about what went wrong.
 */
static void nrf_qwr_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}


uint8_t buffer_tx[20] = {0};
static void cus_evt_handler(ble_cus_t * p_cus, ble_cus_evt_t * p_evt)
{  
  switch(p_evt->evt_type)
  {
    case BLE_LEDS_STATES_CHAR_EVT_COMMAND_RX:
    {
		  if(p_evt->params_command.command_data.p_data[0] == 0XFC){
          for(int i=0;i<1000;i++)
          {
           buffer_tx[0] = 0xFC
          }
 
         }

         else{
            NRF_LOG_INFO("Invalid Command found");
         }
 
    }break;

    case BLE_BUTTONS_STATES_CHAR_NOTIFICATIONS_ENABLED:
    {
        NRF_LOG_INFO("buttons states char notifications are enabled.");

    } break;

    case BLE_BUTTONS_STATES_CHAR_NOTIFICATIONS_DISABLED:
    {
        NRF_LOG_INFO("buttons states char notifications are disabled.");

    } break;

    case BLE_POTENTIO_LEVEL_CHAR_NOTIFICATIONS_ENABLED:
    {
        NRF_LOG_INFO("potentio level char notifications are enabled.");

    } break;

    case BLE_POTENTIO_LEVEL_CHAR_NOTIFICATIONS_DISABLED:
    {
        NRF_LOG_INFO("potentio level char notifications are disabled.");

    } break;

    default:
    break;
  }
}


/**@brief Function for initializing the Custom ble service.
 */
static void cus_init(void)
{
   ret_code_t          err_code;
   ble_cus_init_t      cus_init = {0};

   cus_init.evt_handler  = cus_evt_handler; 

   err_code = ble_cus_init(&m_cus, &cus_init);
   APP_ERROR_CHECK(err_code);
} 



static void services_init(void)
{
    uint32_t           err_code;
    nrf_ble_qwr_init_t qwr_init = {0};
    ble_dis_init_t     dis_init;
    // Initialize Queued Write Module.
    qwr_init.error_handler = nrf_qwr_error_handler;
    err_code = nrf_ble_qwr_init(&m_qwr, &qwr_init);
    APP_ERROR_CHECK(err_code);
    cus_init();
    bas_init();
    #if OTA_CODE_ENABLED
      ble_dfu_buttonless_init_t dfus_init =
      {
          .evt_handler = ble_dfu_evt_handler
      };
      err_code = ble_dfu_buttonless_init(&dfus_init);
      APP_ERROR_CHECK(err_code);
    #endif
    // Initialize Device Information Service.
    memset(&dis_init, 0, sizeof(dis_init));

    ble_srv_ascii_to_utf8(&dis_init.manufact_name_str, "TITAN");
    ble_srv_ascii_to_utf8(&dis_init.model_num_str, "NORDIC");
    ble_srv_ascii_to_utf8(&dis_init.serial_num_str, "NORDIC");
    ble_srv_ascii_to_utf8(&dis_init.hw_rev_str, "1.0");
    ble_srv_ascii_to_utf8(&dis_init.fw_rev_str, "1.0");
    dis_init.dis_char_rd_sec = SEC_OPEN;

    err_code = ble_dis_init(&dis_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling an event from the Connection Parameters Module.
 *
 * @details This function will be called for all events in the Connection Parameters Module
 *          which are passed to the application.
 *
 * @note All this function does is to disconnect. This could have been done by simply setting
 *       the disconnect_on_fail config parameter, but instead we use the event handler
 *       mechanism to demonstrate its use.
 *
 * @param[in] p_evt  Event received from the Connection Parameters Module.
 */
static void on_conn_params_evt(ble_conn_params_evt_t * p_evt)
{
    uint32_t err_code;

    if (p_evt->evt_type == BLE_CONN_PARAMS_EVT_FAILED)
    {
        err_code = sd_ble_gap_disconnect(m_conn_handle, BLE_HCI_CONN_INTERVAL_UNACCEPTABLE);
        APP_ERROR_CHECK(err_code);
    }
}


/**@brief Function for handling errors from the Connection Parameters module.
 *
 * @param[in] nrf_error  Error code containing information about what went wrong.
 */
static void conn_params_error_handler(uint32_t nrf_error)
{
    APP_ERROR_HANDLER(nrf_error);
}


/**@brief Function for initializing the Connection Parameters module.
 */
static void conn_params_init(void)
{
    uint32_t               err_code;
    ble_conn_params_init_t cp_init;

    memset(&cp_init, 0, sizeof(cp_init));

    cp_init.p_conn_params                  = NULL;
    cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
    cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
    cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
    cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
    cp_init.disconnect_on_fail             = false;
    cp_init.evt_handler                    = on_conn_params_evt;
    cp_init.error_handler                  = conn_params_error_handler;

    err_code = ble_conn_params_init(&cp_init);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for putting the chip into sleep mode.
 *
 * @note This function will not return.
 */

static void sleep_mode_enter(void)
{
    ret_code_t err_code;
    err_code = sd_power_system_off();
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling advertising events.
 *
 * @details This function will be called for advertising events which are passed to the application.
 *
 * @param[in] ble_adv_evt  Advertising event.
 */
static void on_adv_evt(ble_adv_evt_t ble_adv_evt)
{
    uint32_t err_code;

    switch (ble_adv_evt)
    {
        case BLE_ADV_EVT_FAST:
            break;
        case BLE_ADV_EVT_IDLE:
            sleep_mode_enter();
            break;
        default:
            break;
    }
}


/**@brief Function for starting advertising.
 */
static void advertising_start(bool erase_bonds)
{
    ret_code_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
    APP_ERROR_CHECK(err_code);
}

/**@brief Function for handling BLE events.
 *
 * @param[in]   p_ble_evt   Bluetooth stack event.
 * @param[in]   p_context   Unused.
 */
static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    uint32_t err_code;
    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:
            //printf("BLE Connected");
            NRF_LOG_INFO("Connected");
            ble_connection_flag = 1;
            m_conn_handle = p_ble_evt->evt.gap_evt.conn_handle;
            err_code = nrf_ble_qwr_conn_handle_assign(&m_qwr, m_conn_handle);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GAP_EVT_DISCONNECTED:
            //printf("BLE disconnected");
            NRF_LOG_INFO("Disconnected");
            ble_connection_flag = 0;
            // LED indication will be changed when advertising starts.
            m_conn_handle = BLE_CONN_HANDLE_INVALID;            
            break;
        case BLE_GAP_EVT_PHY_UPDATE_REQUEST:
        {
            NRF_LOG_DEBUG("PHY update request.");
            ble_gap_phys_t const phys =
            {
                .rx_phys = BLE_GAP_PHY_AUTO,
                .tx_phys = BLE_GAP_PHY_AUTO,
            };
            err_code = sd_ble_gap_phy_update(p_ble_evt->evt.gap_evt.conn_handle, &phys);
            APP_ERROR_CHECK(err_code);
        } break;

        case BLE_GAP_EVT_SEC_PARAMS_REQUEST:
            // Pairing not supported
            err_code = sd_ble_gap_sec_params_reply(m_conn_handle, BLE_GAP_SEC_STATUS_PAIRING_NOT_SUPP, NULL, NULL);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTS_EVT_SYS_ATTR_MISSING:
            // No system attributes have been stored.
            err_code = sd_ble_gatts_sys_attr_set(m_conn_handle, NULL, 0, 0);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTC_EVT_TIMEOUT:
            // Disconnect on GATT Client timeout event.
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gattc_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

        case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;
        case BLE_GATTS_EVT_WRITE:
             tx_complete_flag = 0;
             break;
        case BLE_GATTS_EVT_HVN_TX_COMPLETE:
            tx_complete_flag = 0;
            break;
        default:
            // No implementation needed.
            break;
    }
}


/**@brief Function for the SoftDevice initialization.
 *
 * @details This function initializes the SoftDevice and the BLE event interrupt.
 */
static void ble_stack_init(void)
{
    ret_code_t err_code;

    err_code = nrf_sdh_enable_request();
    APP_ERROR_CHECK(err_code);

    // Configure the BLE stack using the default settings.
    // Fetch the start address of the application RAM.
    uint32_t ram_start = 0;
    err_code = nrf_sdh_ble_default_cfg_set(APP_BLE_CONN_CFG_TAG, &ram_start);
    APP_ERROR_CHECK(err_code);

    // Enable BLE stack.
    err_code = nrf_sdh_ble_enable(&ram_start);
    APP_ERROR_CHECK(err_code);

    // Register a handler for BLE events.
    NRF_SDH_BLE_OBSERVER(m_ble_observer, APP_BLE_OBSERVER_PRIO, ble_evt_handler, NULL);
}


/**@brief Function for handling events from the GATT library. */
void gatt_evt_handler(nrf_ble_gatt_t * p_gatt, nrf_ble_gatt_evt_t const * p_evt)
{
    if ((m_conn_handle == p_evt->conn_handle) && (p_evt->evt_id == NRF_BLE_GATT_EVT_ATT_MTU_UPDATED))
    {
        m_ble_nus_max_data_len = p_evt->params.att_mtu_effective - OPCODE_LENGTH - HANDLE_LENGTH;
        NRF_LOG_INFO("Data len is set to 0x%X(%d)", m_ble_nus_max_data_len, m_ble_nus_max_data_len);
    }
    NRF_LOG_DEBUG("ATT MTU exchange completed. central 0x%x peripheral 0x%x",
                  p_gatt->att_mtu_desired_central,
                  p_gatt->att_mtu_desired_periph);
}


/**@brief Function for initializing the GATT library. */
void gatt_init(void)
{
    ret_code_t err_code;

    err_code = nrf_ble_gatt_init(&m_gatt, gatt_evt_handler);
    APP_ERROR_CHECK(err_code);

    err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_SDH_BLE_GATT_MAX_MTU_SIZE);
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for initializing the Advertising functionality.
 */
static void advertising_init(void)
{
    uint32_t               err_code;
    ble_advertising_init_t init;

    memset(&init, 0, sizeof(init));

    init.advdata.name_type          = BLE_ADVDATA_FULL_NAME;
    init.advdata.include_appearance = false;
    init.advdata.flags              = BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE;

    init.srdata.uuids_complete.uuid_cnt = sizeof(m_adv_uuids) / sizeof(m_adv_uuids[0]);
    init.srdata.uuids_complete.p_uuids  = m_adv_uuids;

    init.config.ble_adv_fast_enabled  = true;
    init.config.ble_adv_fast_interval = APP_ADV_INTERVAL;
    init.config.ble_adv_fast_timeout  = APP_ADV_DURATION;
    init.evt_handler = on_adv_evt;

    err_code = ble_advertising_init(&m_advertising, &init);
    APP_ERROR_CHECK(err_code);

    ble_advertising_conn_cfg_tag_set(&m_advertising, APP_BLE_CONN_CFG_TAG);
}


/**@brief Function for initializing the nrf log module.
 */
static void log_init(void)
{
    ret_code_t err_code = NRF_LOG_INIT(NULL);
    APP_ERROR_CHECK(err_code);
    //NRF_LOG_DEFAULT_BACKENDS_INIT();
}


/**@brief Function for initializing power management.
 */
static void power_management_init(void)
{
    ret_code_t err_code;
    err_code = nrf_pwr_mgmt_init();
    APP_ERROR_CHECK(err_code);
}


/**@brief Function for handling the idle state (main loop).
 *
 * @details If there is no pending log operation, then sleep until next the next event occurs.
 */
static void idle_state_handle(void)
{
    if (NRF_LOG_PROCESS() == false)
    {
        nrf_pwr_mgmt_run();
    }
}
void ble_cus_send_sensor_data(int8_t *data, uint16_t len)
{
      ret_code_t err_code;
      uint32_t timer = millis();
      do{
        err_code = ble_cus_sensor_state_update(&m_cus, data, len, m_conn_handle);
      }while(err_code == BLE_ERROR_GATTS_SYS_ATTR_MISSING && millis() - timer < 3000);
      if ( err_code != NRF_SUCCESS                   &&
           err_code != BLE_ERROR_INVALID_CONN_HANDLE &&
           err_code != NRF_ERROR_INVALID_STATE       &&
           err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)
      {

        APP_ERROR_CHECK(err_code);
      }
}
static void lfclk_config(void)
{
    ret_code_t err_code = nrf_drv_clock_init();
    APP_ERROR_CHECK(err_code);
    nrf_drv_clock_lfclk_request(NULL);
}
void power_manage(void)
{
    __set_FPSCR(__get_FPSCR()  & ~(FPU_EXCEPTION_MASK));      
    (void) __get_FPSCR();
    NVIC_ClearPendingIRQ(FPU_IRQn);

    uint32_t err_code = sd_app_evt_wait();
    APP_ERROR_CHECK(err_code);
}
static void configure_watchdog(){
    //Configure WDT.
    ret_code_t err_code;
    nrf_drv_wdt_config_t config = NRF_DRV_WDT_DEAFULT_CONFIG;
    err_code = nrf_drv_wdt_init(&config, wdt_event_handler);
    APP_ERROR_CHECK(err_code);
    err_code = nrf_drv_wdt_channel_alloc(&m_channel_id);
    APP_ERROR_CHECK(err_code);
    nrf_drv_wdt_enable();
}


void init_all_peripherials(){
    ret_code_t err_code;
    bool erase_bonds;
    #if OTA_CODE_ENABLED
      //err_code = ble_dfu_buttonless_async_svci_init();
      //APP_ERROR_CHECK(err_code);
    #endif
    pwm_init();
    init_rtc_app();
    timers_init();
    configure_watchdog();
    scheduler_init();
    //AFS_Init();


    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();
    saadc_init();
    application_timers_start();
    advertising_start(erase_bonds);
    err_code = sd_ble_gap_tx_power_set(BLE_GAP_TX_POWER_ROLE_CONN, m_advertising.adv_handle, 0); 
    APP_ERROR_CHECK(err_code); 
}
int main(void)
{
    init_all_peripherials();
    //printf("TESTING \n");
    while(1)
    {
        app_sched_execute();

    }
}
#endif

Fullscreen 7838.ble_cus.c Download

/*
 * ble_cus.c file for the custom ble service
 *
 * Author : Abdelali Boussetta  github/rmptxf
 * Date : 01/30/2019
 *
 */

#include "ble_cus.h"


/**@brief Function for handling the Write event.
 *
 * @param[in]   p_cus       Custom service structure.
 * @param[in]   p_ble_evt   Event received from the BLE stack.
 */
static void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
{
    ble_gatts_evt_write_t const * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    ble_cus_evt_t                 evt;
  // writing to the leds states characteristic
   if (p_evt_write->handle == p_cus->leds_states_char_handles.value_handle)
    { 
        evt.params_command.command_data.p_data = p_evt_write->data;
        evt.params_command.command_data.length = p_evt_write->len;
        evt.evt_type = BLE_LEDS_STATES_CHAR_EVT_COMMAND_RX; 
        p_cus->evt_handler(p_cus, &evt);
    }

    // writing to the buttons states characteristic (cccd) "client characteristic configuration descriptor"
    else if (p_evt_write->handle == p_cus->buttons_states_char_handles.cccd_handle)
    {
      if (ble_srv_is_notification_enabled(p_evt_write->data))
      {
          evt.evt_type = BLE_BUTTONS_STATES_CHAR_NOTIFICATIONS_ENABLED;
      }
      else
      {
          evt.evt_type = BLE_BUTTONS_STATES_CHAR_NOTIFICATIONS_DISABLED;
      }

      p_cus->evt_handler(p_cus, &evt);
    }

    // writing to the potentiometer level characteristic (cccd)
    else if (p_evt_write->handle == p_cus->potentio_level_char_handles.cccd_handle)
    {
      if (ble_srv_is_notification_enabled(p_evt_write->data))
      {
          evt.evt_type = BLE_POTENTIO_LEVEL_CHAR_NOTIFICATIONS_ENABLED;
      }
      else
      {
          evt.evt_type = BLE_POTENTIO_LEVEL_CHAR_NOTIFICATIONS_DISABLED;
      }

      p_cus->evt_handler(p_cus, &evt);
    }
}


/**@brief Function for handling the Custom servie ble events.
 *
 * @param[in]   p_ble_evt   Event received from the BLE stack.
 */
void ble_cus_on_ble_evt( ble_evt_t const * p_ble_evt, void * p_context)
{
    ble_cus_t * p_cus = (ble_cus_t *) p_context;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GATTS_EVT_WRITE:
            on_write(p_cus, p_ble_evt);
            break;

        default:
            // No implementation needed.
            break;
    }
}

/**@brief Function for initializing the Custom ble service.
 *
 * @param[in]   p_cus       Custom service structure.
 * @param[in]   p_cus_init  Information needed to initialize the service.
 *
 * @return      NRF_SUCCESS on success, otherwise an error code.
 */

uint32_t ble_cus_init(ble_cus_t * p_cus, const ble_cus_init_t * p_cus_init)
{

    uint32_t                  err_code;
    ble_uuid_t                ble_uuid;
    ble_add_char_params_t     add_char_params;

/* Adding the service */

    // Initialize service structure.
    p_cus->evt_handler               = p_cus_init->evt_handler;
    p_cus->conn_handle               = BLE_CONN_HANDLE_INVALID;

    // Add the Custom ble Service UUID
    ble_uuid128_t base_uuid =  CUS_SERVICE_UUID_BASE;
    err_code =  sd_ble_uuid_vs_add(&base_uuid, &p_cus->uuid_type);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }
    
    ble_uuid.type = p_cus->uuid_type;
    ble_uuid.uuid = CUS_SERVICE_UUID;

    // Add the service to the database
    err_code = sd_ble_gatts_service_add(BLE_GATTS_SRVC_TYPE_PRIMARY, &ble_uuid, &p_cus->service_handle);
    if (err_code != NRF_SUCCESS)
    {
        return err_code;
    }

    uint8_t leds_char_init_value [2] = {0};

    memset(&add_char_params, 0, sizeof(add_char_params));
    add_char_params.uuid             = LEDS_STATES_CHAR_UUID;
    add_char_params.uuid_type        = p_cus->uuid_type;

    add_char_params.max_len                  = 25;
    add_char_params.init_len                 = 1;
    add_char_params.char_props.write         = 1;
    add_char_params.char_props.write_wo_resp = 1;
    add_char_params.char_props.read   = 1;
    add_char_params.char_props.notify = 1;
    //add_char_params.init_len          = 1; // (in bytes)
    //add_char_params.max_len           = 4;
    //add_char_params.p_init_value      = leds_char_init_value;



    add_char_params.read_access       = SEC_OPEN;
    add_char_params.write_access      = SEC_OPEN;
    add_char_params.cccd_write_access = SEC_OPEN;

    err_code = characteristic_add(p_cus->service_handle, 
                                  &add_char_params, 
                                  &p_cus->leds_states_char_handles);

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

    return NRF_SUCCESS;
}

/**@brief Function for updating the potentio level value on the potentio ble characteristic.
 *
 * @param[in]   p_cus           Custom service structure.
 * @param[in]   potentio_level  Potentiometer level.
 * @param[in]   conn_handle     Connection handle.
 *
 * @return      NRF_SUCCESS on success, otherwise an error code.
 */

uint32_t ble_cus_potentio_level_update(ble_cus_t * p_cus, int8_t* potentio_level, int length, uint16_t conn_handle)
{
    ble_gatts_hvx_params_t params;
    uint16_t len = length;

    memset(&params, 0, sizeof(params));
    params.type   = BLE_GATT_HVX_NOTIFICATION;
    params.handle = p_cus->potentio_level_char_handles.value_handle;
    params.p_data = potentio_level;
    params.p_len  = &len;

    return sd_ble_gatts_hvx(conn_handle, &params);
}

/**@brief Function for updating the buttons states on the buttons ble characteristic.
 *
 * @param[in]   p_cus             Custom service structure.
 * @param[in]   p_buttons_states  Buttons states.
 * @param[in]   conn_handle       Connection handle.
 *
 * @return      NRF_SUCCESS on success, otherwise an error code.
 */

uint32_t ble_cus_buttons_states_update(ble_cus_t * p_cus, int8_t  * p_buttons_states, uint16_t conn_handle)
{
    ble_gatts_hvx_params_t params;
    uint16_t len = sizeof(p_buttons_states);

    memset(&params, 0, sizeof(params));
    params.type   = BLE_GATT_HVX_NOTIFICATION;
    params.handle = p_cus->buttons_states_char_handles.value_handle;
    params.p_data = p_buttons_states;
    params.p_len  = &len;

    return sd_ble_gatts_hvx(conn_handle, &params);
}
uint32_t ble_cus_sensor_state_update(ble_cus_t * p_cus, int8_t  * p_buttons_states, int length, uint16_t conn_handle)
{
    ble_gatts_hvx_params_t params;
    uint16_t len = length;

    memset(&params, 0, sizeof(params));
    params.type   = BLE_GATT_HVX_NOTIFICATION;
    params.handle = p_cus->leds_states_char_handles.value_handle;
    params.p_data = p_buttons_states;
    params.p_len  = &len;

    return sd_ble_gatts_hvx(conn_handle, &params);
}

5775.ble_cus.h

Hi Edvin,

Now,as you mentioned, there are two different event hanler,
1. ble_evt_handler in main.c
2. ble_cus_on_ble_evt in ble_cus.c

Now, when I trying to send packets continuously,my code is getting stuck and I am unable to send the data to BLE.
I tried above suggestions, somehow it doesn't seem to work for me, as the code is getting stuck. Please check the code and let me know if any changes required in order to solve the issue.

I would really appreciate if you can let me know on how to apply your suggested changes in my code.

thanks

[Edvin]

Where is it stuck? In ble_cus_send_sensor_data()?

BR,

Edvin

[Mushtakh Shaikh]

Yes, Edwin, it is stuck in ble_cus_send_sensor_data and the below function returns the error.

uint32_t ble_cus_sensor_state_update(ble_cus_t * p_cus, int8_t * p_buttons_states, int length, uint16_t conn_handle)
{
ble_gatts_hvx_params_t params;
uint16_t len = length;
uint32_t err_code;

memset(&params, 0, sizeof(params));
params.type = BLE_GATT_HVX_NOTIFICATION;//BLE_GATT_HVX_NOTIFICATION;
params.handle = p_cus->leds_states_char_handles.value_handle;
params.p_data = p_buttons_states;
params.p_len = &len;

return sd_ble_gatts_hvx(conn_handle, &params);
}

[Mushtakh Shaikh]

Hi Edwin,

Can you please suggest any changes if required?

Or any mistake in my implementations??

[Edvin]

So what does it return?

I did notice that you didn't follow the suggestion that I mentioned in my pseudo code snippet, to leave the event and trigger the sending from another place (see what I did with the send_data_flag parameter).

However, when you are stuck, what does ble_cus_sensor_state_update() return? It is not NRF_ERROR_RESOURCES, because according to your ble_cus_send_sensor_data(), because if it did, it would be passed onto the APP_ERROR_CHECK(err_code), and the application would restart.

Does it return BLE_ERROR_GATTS_SYS_ATTR_MISSING? If so, what is the expected behavior? Because now it will keep trying, but your timer parameter will not change.

Best regards,

Edvin