Send Bluetooth Data Continuously

Question

I'm not sure if what I am trying to do is the proper way to send ble data, and I since I can't get it to work, I'm assuming I'm doing it wrong. What I'm trying to do is send data to a BLE central device (my phone) using a peripheral. after initializing everything I can send and receive data from a serial port monitor just fine. The code below is what grabs the serial port data and sends it to the central device.

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void uart_event_handle(app_uart_evt_t *p_event) {
  static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
  static uint8_t index = 0;
  uint32_t err_code;
  switch (p_event->evt_type) {
  case APP_UART_DATA_READY:
    UNUSED_VARIABLE(app_uart_get(&data_array[index]));
    index++;
    if ((data_array[index - 1] == '\n') ||
        (data_array[index - 1] == '\r') ||
        (index >= m_ble_nus_max_data_len)) {
      if (index > 1) {
        printf("\n\n\n\rReady to send data over BLE NUS.");
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        printf("\n\rm_conn_handle = %d", m_conn_handle);
        NRF_LOG_HEXDUMP_DEBUG(data_array, index);
        do {
          uint16_t length = (uint16_t)index;
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void uart_event_handle(app_uart_evt_t *p_event) {
  static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
  static uint8_t index = 0;
  uint32_t err_code;

  switch (p_event->evt_type) {
  case APP_UART_DATA_READY:
    UNUSED_VARIABLE(app_uart_get(&data_array[index]));
    index++;

    if ((data_array[index - 1] == '\n') ||
        (data_array[index - 1] == '\r') ||
        (index >= m_ble_nus_max_data_len)) {
      if (index > 1) {
        printf("\n\n\n\rReady to send data over BLE NUS.");
        NRF_LOG_DEBUG("Ready to send data over BLE NUS");
        printf("\n\rm_conn_handle = %d", m_conn_handle);
        NRF_LOG_HEXDUMP_DEBUG(data_array, index);

        do {
          uint16_t length = (uint16_t)index;
          err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
          if ((err_code != NRF_ERROR_INVALID_STATE) &&
              (err_code != NRF_ERROR_RESOURCES) &&
              (err_code != NRF_ERROR_NOT_FOUND)) {
            APP_ERROR_CHECK(err_code);
          }
        } while (err_code == NRF_ERROR_RESOURCES);
      }

      index = 0;
    }
    break;

  case APP_UART_COMMUNICATION_ERROR:
    APP_ERROR_HANDLER(p_event->data.error_communication);
    break;

  case APP_UART_FIFO_ERROR:
    APP_ERROR_HANDLER(p_event->data.error_code);
    break;

  default:
    break;
  }
}

I thought that I could take the same concept to send data from the main method. after initializing, I put the following code, which (I thought) sent "Hello\n" every 2.5 seconds. instead, "m_conn_handle" = 0xFFFF and it never transmits data. NOTE: I am connected to the device via my phone which I thought should change that value to 0x0000. I know the code is rough but I just wanted to make sure I could send data correctly before I went any further. And I can't.

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while (1) {  
  static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
  data_array[0] = 'H';
  data_array[1] = 'e';
  data_array[2] = 'l';
  data_array[3] = 'l';
  data_array[4] = 'o';
  data_array[5] = '\n';
  ret_code_t err_code = 0;
  uint8_t index = 6;
  printf("\n\rm_conn_handle = %d", m_conn_handle);
  if ((data_array[index - 1] == '\n') ||
      (data_array[index - 1] == '\r') ||
      (index >= m_ble_nus_max_data_len)) {
    if (index > 1) {
      printf("\n\rGonna broadcast now!");
      NRF_LOG_DEBUG("Gonna broadcast now?");
      NRF_LOG_HEXDUMP_DEBUG(data_array, index);
      do {
        uint16_t length = (uint16_t)index;
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while (1) {  
  static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
  data_array[0] = 'H';
  data_array[1] = 'e';
  data_array[2] = 'l';
  data_array[3] = 'l';
  data_array[4] = 'o';
  data_array[5] = '\n';
  ret_code_t err_code = 0;
  uint8_t index = 6;
  printf("\n\rm_conn_handle = %d", m_conn_handle);
  if ((data_array[index - 1] == '\n') ||
      (data_array[index - 1] == '\r') ||
      (index >= m_ble_nus_max_data_len)) {
    if (index > 1) {
      printf("\n\rGonna broadcast now!");
      NRF_LOG_DEBUG("Gonna broadcast now?");
      NRF_LOG_HEXDUMP_DEBUG(data_array, index);

      do {
        uint16_t length = (uint16_t)index;
        err_code = ble_nus_data_send(&m_nus, data_array, &length, m_conn_handle);
        if ((err_code != NRF_ERROR_INVALID_STATE) &&
            (err_code != NRF_ERROR_RESOURCES) &&
            (err_code != NRF_ERROR_NOT_FOUND)) {
          APP_ERROR_CHECK(err_code);
        }
      } while (err_code == NRF_ERROR_RESOURCES);
    }

    index = 0;
  }
  nrf_delay_ms(2500);
}

If anyone knows what I need to do to get it to send data, that would be greatly appreciated.

On a similar note, I am able to process that data from the central that I am receiving on the peripheral using the static void nus_data_handler(ble_nus_evt_t *pevt) function as follows.

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static void nus_data_handler(ble_nus_evt_t *p_evt) {
  if (p_evt->type == BLE_NUS_EVT_RX_DATA) {
    if(p_evt->params.rx_data.p_data[0] == 'V') {
      uint16_t value = p_evt->params.rx_data.p_data[1] << 8 | p_evt->params.rx_data.p_data[2];
      printf("\n\rSetting Value to %d\n\r", value);
      write_value(value);
    }
  }
}
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static void nus_data_handler(ble_nus_evt_t *p_evt) {

  if (p_evt->type == BLE_NUS_EVT_RX_DATA) {
    if(p_evt->params.rx_data.p_data[0] == 'V') {
      uint16_t value = p_evt->params.rx_data.p_data[1] << 8 | p_evt->params.rx_data.p_data[2];
      printf("\n\rSetting Value to %d\n\r", value);
      write_value(value);
    }
  }
}

Is this the proper way to read the value being received? It works fine, but that doesn't mean I'm doing it right.

Collin NB · Accepted Answer

The problem was completely on my end. I'm just starting to use C again after 2 years of C# and keep getting tripped up on some of the basics. I defined m_conn_handle in a different file as static not extern.