Gatt connection writing via nrf_connect app only receiving a single byte

[Thomas]

Hi,

I have a modified template of the ble_app_template example from sdk 15 NRF58240-dk pca 10056 s140.

I have written a custom function as per this tutorial : https://github.com/bjornspockeli/custom_ble_service_example

I am using the onwrite function to read data that I send via a NRF connect app. However, I wish to have a longer amount of data sent than a byte. But when I change my variable from a uint8 to anything bigger it does not read the data. Regardless of if I use the NRF connect app to send a byte, uint8 or uint16.

What could be my issue thanks,

Here is my on_write code. Works when using found_data(uint8) and sending a byte or uint8 via nrf connect.

void on_write(ble_cus_t * p_cus, ble_evt_t const * p_ble_evt)
{
    ble_gatts_evt_write_t * p_evt_write = &p_ble_evt->evt.gatts_evt.params.write;
    uint8_t found_data;
    //uint16_t found_data;
    
    // Check if the handle passed with the event matches the Custom Value Characteristic handle.
    if (p_evt_write->handle == p_cus->custom_value_handles.value_handle)
    {
        memcpy(&found_data, p_ble_evt->evt.gatts_evt.params.write.data, p_ble_evt->evt.gatts_evt.params.write.len);
        nrf_gpio_pin_toggle(LED_4); 
        NRF_LOG_INFO("data is: %d",found_data);
        if(found_data == 77){
            NRF_LOG_INFO("Dummy test passed");
        }
    }
}

Note I put a little test in if the value is 77 which passes when a 77 uint is passed in.

[Mttrinh]

Hi,

But when I change my variable from a uint8 to anything bigger it does not read the data.

Can you give more details on what you mean by "does not read data"? Is the data wrong? No data? Any error codes? 

[Thomas]

The data was not wrong it was just always empty. I recreated it again in another example and it now works. I am not specifically sure why it did not. Could be the data I was passing into the function was not the correct size. I changed it to a uint32_t and am now passing in integer values.