Currently I am using the NRF52 device to connect with a custom peripheral. The current goal I am trying to reach is toggling an LED by sending the command 0x8900 through Service UUID 0x0001 with Characterisic ID 0x0002.
This is a write command that I have tested using the LightBlue phone app. The app successfully toggles the peripheral LED.
I began with the BLE UART Central code and modified the NUS service routine to be custom. The terminal shown below is the output I receive when pair and discover the device.
I assign the write characteristic 0x0002 with Handle value 0x000E to the TX Handler. Once completed I initiate a message that is sent successfully.
The function for the message send code is here:
uint32_t ble_nus_c_string_send(ble_nus_c_t * p_ble_nus_c, uint8_t * p_string, uint16_t length)
{ int i; VERIFY_PARAM_NOT_NULL(p_ble_nus_c);
if (length > BLE_NUS_MAX_DATA_LEN)
{
return NRF_ERROR_INVALID_PARAM;
}
if ( p_ble_nus_c->conn_handle == BLE_CONN_HANDLE_INVALID)
{
return NRF_ERROR_INVALID_STATE;
}
const ble_gattc_write_params_t write_params = {
.write_op = BLE_GATT_OP_WRITE_CMD,
.flags = BLE_GATT_EXEC_WRITE_FLAG_PREPARED_WRITE,
.handle = p_ble_nus_c->handles.nus_control_handle,
.offset = 0,
.len = length,
.p_value = p_string
};
printf("\r\nMessage: %02x ",write_params.write_op);
printf("%02x ",write_params.flags);
printf("%02x ",write_params.handle >> 8);
printf("%02x ",write_params.handle & 0x00FF);
printf("%02x ",write_params.offset >> 8);
printf("%02x ",write_params.offset & 0x00FF);
printf("%02x ",write_params.len >> 8);
printf("%02x ",write_params.len & 0x00FF);
for(i=0; i< write_params.len;i++)
{
printf("%02x ",write_params.p_value[i]);
}
printf("\r\n");
return sd_ble_gattc_write(p_ble_nus_c->conn_handle, &write_params);
}
The message is a length of two bytes simply containing 0x8900. I am extremely new to BLE and don't know what the proper development steps are to prove that each step in the setup is performing properly. I do believe that the discovery and pairing is working correctly.
It just doesn't seem like the function sd_ble_gattc_write() is working correctly with the parameters I am passing in. Please let me know if the information I provided is not helpful. I can add anything that may be of value.
Additional Information 1: I changed the write from BLE_GATT_OP_WRITE_CMD to BLE_GATT_OP_WRITE_REQ and printed out the value in p_ble_evt->evt.gattc_evt.gatt_status from the response.
The GATT Status is 0x0105 which corresponds to BLE_GATT_STATUS_ATTERR_INSUF_AUTHENTICATION. I am working on resolving this at the moment. I appreciate any input.
