UART close breakes whole communication

RE: UART close breakes whole communication

mhuk_ — Fri, 24 May 2019 12:43:23 GMT

Thanks, it works as a charm now.

RE: UART close breakes whole communication

Jørgen Holmefjord — Fri, 24 May 2019 07:34:33 GMT

You should wait until you get the APP_UART_TX_EMPTY event in the handler. And I recommend that you exit the scan_evt_handler before doing any delayin, it might run at a higher priority that will block your transfer from starting.

RE: UART close breakes whole communication

mhuk_ — Thu, 23 May 2019 15:00:52 GMT

The purpose is to decrease power consumption.

I've tried to configure UART in blocking mode (without UART handler). Even though it wasn't working
How to close UART after the transmission has been finished in smart way? Simple delay for a second doesn't work.

RE: UART close breakes whole communication

Jørgen Holmefjord — Thu, 23 May 2019 14:49:09 GMT

I'm not sure I understand the purpose of the app_uart_close call. You are transferring data with app_uart_put inside the handler and the transfers will most likely not start because you close the UART right after queuing the data for transfer. Note that app_uart_put is a non-blocking function that will only put the data into the transfer queue before returning, the actual transfer will happen asynchronously.

RE: UART close breakes whole communication

mhuk_ — Wed, 22 May 2019 13:52:22 GMT

Hello Jorgen,

DEBUG_ON flag is undefined, here is the example when it doesn't work (uart_init is initialized in main()). When you comment out app_uart_close() it works. If uart_init is moved to the timeout event right before sending it still works without app_uart_close() and doesn't work with it.

/**@brief Function for handling Scanning Module events.
 */
static void scan_evt_handler(scan_evt_t const * p_scan_evt)
{
	switch(p_scan_evt->scan_evt_id)
	{
		case NRF_BLE_SCAN_EVT_SCAN_TIMEOUT:
		{
            //doing some Math here .....
            
			//fill in final beacon_scan_result packet with 5 closest beacons
			for (uint16_t i = 0; i < SAMPLES_UART_NUM; i++)
			{
				ui32ToByteArray((uint32_t)((maj_result[i] << 16) | min_result[i]), &beacon_scan_result[i * SAMPLES_PACKET_SIZE]);
				floatToByteArray(rssi_result[i], &beacon_scan_result[i * SAMPLES_PACKET_SIZE + 4]);
			}

			//uart_flag = 1;
			for (uint16_t i = 0; i < SAMPLES_UART_NUM * SAMPLES_PACKET_SIZE; i++)
			{
				while(app_uart_put(beacon_scan_result[i]) != NRF_SUCCESS){};
			}

			app_uart_close();
			//uart_flag = 0;

			#ifdef DEBUG_ON
				SEGGER_RTT_printf(0, "\nUART data sent and port closed\n");
				SEGGER_RTT_printf(0, "___________________________\n");
			#endif
		} break;

		default:
		  break;
	}
}

Commented out uart_flag was used to test point #3 and I didn't notice any difference there. My example is based on the ble_app_uart example.

Error codes of what functions? app_uart_close doesn't have any meaningful error codes as for me.

Kind regards,

Max

RE: UART close breakes whole communication

Jørgen Holmefjord — Wed, 22 May 2019 12:54:51 GMT

Hi,

Can you post the code where you transmit data, and where you call app_uart_close? Are you checking the error codes from the functions?

Best regards,
Jørgen