[ECOS] E7T loosing data on serial port reception?

[ECOS] E7T loosing data on serial port reception?

[Carsten Andersen]

I'm loosing chunks of data when trying to receive on the serial port on the
E7T.

I'm running the reception and transmission in two different threads and the
main program in the main thread. Basically I open the port:

	fd = open("/dev/termios0", O_RDWR | O_NOCTTY);
	fcntl(fd, F_SETFL, 0);

Then I configure the port:

	struct termios options;

	tcgetattr(fd, &options);

	cfsetispeed(&options, B9600);
	cfsetospeed(&options, B9600);

	/* 8E2 */
	options.c_cflag |= PARENB;
	options.c_cflag &= ~PARODD;
	options.c_cflag |= CSTOPB;
	options.c_cflag &= ~CSIZE;
	options.c_cflag |= CS8;

	options.c_cflag &= ~CRTSCTS;
/* disable HW flow control */

	options.c_cflag |= (CLOCAL | CREAD);
/* local line - do not change owner of port, enable receiver */

	options.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK | ECHONL | ISIG);
/* raw input, disable echo, no echo erase, disable signals */

	options.c_oflag &= ~(OPOST | ONLCR);
/* raw output */

	options.c_iflag |= (IGNPAR | ISTRIP);
/* ignore parity errors (we want the data even when it contains errors!),
strip parity bits */
	options.c_iflag &= ~(PARMRK | BRKINT | ICRNL);

	/* wait for at least 1 character, blocking */
	options.c_cc[VMIN] = 1;
	options.c_cc[VTIME] = 0;

	tcsetattr(fd, TCSANOW, &options);

And then I start the threads:

	pthread_create(&reader_thread, NULL, readerThread, NULL);
	pthread_create(&writer_thread, NULL, writerThread, NULL);

I have some receive and transmit buffers protected by the mutexes and I wait
for a transmitQueueNotEmptyCondition when there's nothing to transmit.

The reception thread looks like this:

static void * readerThread(void * threadParameter)
{
	int	numberOfBytesRead;
	uint32_t	currentNumberOfBytes;

	pthread_mutex_lock(&receiveMutex);
	while (1)
	{
		currentNumberOfBytes = UART0_RX_buffer_count;
		pthread_mutex_unlock(&receiveMutex);

		if (currentNumberOfBytes > 0)
		{
			signal_main_to_read_from_buffer();
		}

		if (currentNumberOfBytes + MAX_BYTES_TO_READ > QUEUE_SIZE)
		{
			currentNumberOfBytes = QUEUE_SIZE -
MAX_BYTES_TO_READ;
		}
		else
		{
			currentNumberOfBytes = MAX_BYTES_TO_READ;
		}
		if (currentNumberOfBytes + UART0_RX_in_PTR > QUEUE_SIZE)
		{
			currentNumberOfBytes = QUEUE_SIZE - UART0_RX_in_PTR;
		}

		numberOfBytesRead = read(fd,
&UART0_RX_QUEUE[UART0_RX_in_PTR], currentNumberOfBytes);
		if (numberOfBytesRead > 0)
		{
			UART0_RX_in_PTR += numberOfBytesRead;
			if (UART0_RX_in_PTR >= QUEUE_SIZE)
			{
				UART0_RX_in_PTR = 0;
			}
		}
		else
		{
			numberOfBytesRead = 0;
		}

		pthread_mutex_lock(&receiveMutex);
		UART0_RX_buffer_count += numberOfBytesRead;
	}
	pthread_mutex_unlock(&receiveMutex);
	return NULL;
}

The interrupt buffer is set to 128. I experience drop-outs even at 9600
baud!?!?

Any ideas?

	Carsten.



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