Add service while connection

[Joyce76]

Dears,

I'd like to add service while connection.

Now I am using UART service and want to add HID service when I put button.

How to add HID service while connection?

Could you provide example code?

SDK : nRF5_SDK_14.2.0_17b948a

Base code : ble_app_uart

App : Android

Thank you.

Best Regards,

Joyce

[Sigurd]

Hi,

It is possible to add a service in an active connection. The central would need to do the service discovery again. So you should notify the central with the sd_ble_gatts_service_changed() after you have added the service. On a button press, you could then call the hids_init()/service_init() and then call the sd_ble_gatts_service_changed. I haven’t tested how the phone behaves when a HID service is suddenly added, so you should test if the phone “activates” the HID functionality after the service is added.

Since you are using ble_app_uart, the first step should be to combine one of the HID examples (either ble_app_hids_keyboard or ble_app_hids_mouse) with the ble_app_uart examples. After that you can look into adding the button press functionally. For an example on how to add button press interrupt, take a look at the pin_change_int example in the SDK folder SDK_folder\examples\peripheral\pin_change_int.

[Giang]

Hi Sigurd, how to calculate start_handle and end_handle in sd_ble_gatts_service_changed . I want to and bas_service to nus_service via button . Thank

[Sigurd]

Hi Giang,

You could try something like this:

ret_code_t send_service_changed(uint16_t conn_handle)
{
    static uint16_t start_handle;
    const  uint16_t end_handle = 0xFFFF;
    ret_code_t err_code;

    err_code = sd_ble_gatts_initial_user_handle_get(&start_handle);

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

    do
    {
        err_code = sd_ble_gatts_service_changed(conn_handle, start_handle, end_handle);
        if (err_code == BLE_ERROR_INVALID_ATTR_HANDLE)
        {
            start_handle += 1;
        }
    } while (err_code == BLE_ERROR_INVALID_ATTR_HANDLE);

    return err_code;
}