EPS32 switch from Arduino to IDF - need to find the corresponding BLE function

Question

I've a a working Arduino-code for my project and rewriting this in ESP-IDF.

For the following Arduino line I'm struggling to find the corresponding function for IDF.

static BLEUUID charUUID_tx("0000ff02-0000-1000-8000-00805f9b34fb");
uint8_t reqBasicInfo[7] = {0xdd, 0xa5, 0x3, 0x0, 0xff, 0xfd, 0x77};
BLERemoteCharacteristic *pRemoteCharacteristicTX;
pRemoteCharacteristicTX->writeValue(reqBasicInfo, sizeof(reqBasicInfo));

Do I use esp_ble_gattc_write_char ? What has to be the handle? 0xff02?

Thank you for your input.

Answer 1

You're correct, you can use the esp_ble_gattc_write_char() function as it technically does what you need. However, this is a low level function for which you need to get the characteristic value handle, connection handle, etc. Below is code (copied from here) that shows how this is done:-

case ESP_GATTC_GET_CHAR_EVT:
    if (p_data->get_char.status != ESP_GATT_OK) {
        break;
    }
    ESP_LOGI(GATTC_TAG, "GET CHAR: conn_id = %x, status %d", p_data->get_char.conn_id, p_data->get_char.status);
    ESP_LOGI(GATTC_TAG, "GET CHAR: srvc_id = %04x, char_id = %04x", p_data->get_char.srvc_id.id.uuid.uuid.uuid16, p_data->get_char.char_id.uuid.uuid.uuid16);

    if (p_data->get_char.char_id.uuid.uuid.uuid16 == 0xee01) {
        gl_profile_tab[PROFILE_A_APP_ID].char_id = p_data->get_char.char_id;

        uint8_t value[30];
        for (int i = 0; i < sizeof(value); ++i)
        {
            value[i] = i;
        }
        esp_ble_gattc_write_char(gattc_if,
                                conn_id,
                                &alert_service_id,
                                &gl_profile_tab[PROFILE_A_APP_ID].char_id,
                                sizeof(value),
                                value,
                                ESP_GATT_WRITE_TYPE_RSP,
                                ESP_GATT_AUTH_REQ_NONE);


    }

Another useful references:-

• ESP write Char example