sd_ble_gattc_write not working

RE: sd_ble_gattc_write not working

AndreasF — Tue, 20 Nov 2018 08:39:37 GMT

Hi.

Sorry for the late reply.

I did not notice you tried to write from the peripheral to the central, the API ble_nus_c_string_send() is for the central UART. Can you try the equivalent API for the peripheral UART, ble_nus_string_send().

There is more documentation on the Nordic UART Service API here.

Best regards.

Andreas

RE: sd_ble_gattc_write not working

jf.chenier — Fri, 16 Nov 2018 15:10:11 GMT

I am using the APP_ERROR_CHECK macro to make sure there is no error returned by the ble_nus_c_string_send function. The function is always returning NRF_SUCCESS.

RE: sd_ble_gattc_write not working

AndreasF — Fri, 16 Nov 2018 14:45:40 GMT

Hi.

Have you tried to debug when you attempt to write?

If ble_nus_c_string_send is unsuccessful it should trigger an error

uint32_t ble_nus_c_string_send(ble_nus_c_t * p_ble_nus_c, uint8_t * p_string, uint16_t length)
{
    VERIFY_PARAM_NOT_NULL(p_ble_nus_c);

    if (length > BLE_NUS_MAX_DATA_LEN)
    {
        NRF_LOG_WARNING("Content too long.");
        return NRF_ERROR_INVALID_PARAM;
    }
    if (p_ble_nus_c->conn_handle == BLE_CONN_HANDLE_INVALID)
    {
        NRF_LOG_WARNING("Connection handle invalid.");
        return NRF_ERROR_INVALID_STATE;
    }

    ble_gattc_write_params_t const write_params =
    {
        .write_op = BLE_GATT_OP_WRITE_CMD,
        .flags    = BLE_GATT_EXEC_WRITE_FLAG_PREPARED_WRITE,
        .handle   = p_ble_nus_c->handles.nus_rx_handle,
        .offset   = 0,
        .len      = length,
        .p_value  = p_string
    };

    return sd_ble_gattc_write(p_ble_nus_c->conn_handle, &write_params);
}

As you can see in ble_nus_c.c, check if you get either NRF_ERROR_INVALID_PARAM or NRF_ERROR_INVALID_STATE when you try to debug.

- Andreas