RE: Adding a second characteristic to a custom service

Bryan H — Tue, 21 Feb 2017 14:28:09 GMT

Jørgen, Thank you so much! I feel really stupid for not figuring that out myself. I also had to change my code for updating the photocell reading as below:

if (p_our_service->conn_handle != BLE_CONN_HANDLE_INVALID)
{
    uint16_t               len = 2;
    ble_gatts_hvx_params_t hvx_params;
    memset(&hvx_params, 0, sizeof(hvx_params));
    hvx_params.handle = p_our_service->char_b_handles.value_handle;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
    hvx_params.offset = 0;
    hvx_params.p_len  = &len;
    hvx_params.p_data = (uint8_t*)photoReading_value;
    sd_ble_gatts_hvx(p_our_service->conn_handle, &hvx_params);
}

Thank you again - big help! Bryan

RE: Adding a second characteristic to a custom service

Jørgen Holmefjord — Tue, 21 Feb 2017 09:47:35 GMT

Hi Bryan,

You need to add a new variable holding the handles for the second characteristics. In step 2.D of the tutorial, you are asked to add the member ble_gatts_char_handles_t char_handles; to the struct ble_os_t. You need to add a second member of type ble_gatts_char_handles_t to this struct, holding the handles of your second charactersitics. Your struct can look something like this:

typedef struct
{
    uint16_t                    conn_handle; 
    uint16_t                    service_handle;        
    ble_gatts_char_handles_t    char_a_handles;
    ble_gatts_char_handles_t    char_b_handles;
} ble_os_t;

In the next step, you will use the new handle holder when adding the new characteristics to the GATT table:

err_code = sd_ble_gatts_characteristic_add(p_our_service->service_handle,
                                           &char_md,
                                           &attr_char_value,
                                           &p_our_service->char_b_handles);
APP_ERROR_CHECK(err_code);

Best regards,

Jørgen