PX4-Autopilot/src/systemcmds/tests/test_uart_break.c

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/**
 * @file test_uart_break.c
 * @author Lorenz Meier <lorenz@px4.io>
 * @author David Sidrane <david_s5@nscdg.com>
 */

#include <px4_platform_common/px4_config.h>
#include <px4_platform_common/defines.h>

#include <sys/types.h>
#include <sys/ioctl.h>

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <termios.h>
#include <string.h>

#include "tests_main.h"

#include <math.h>
#include <float.h>

int test_uart_break(int argc, char *argv[])
{
	int uart2_nwrite0 = 0;
	int uart2_nwrite1 = 0;
	int uart2_buffer_size = 0;

	/* assuming NuttShell is on UART1 (/dev/ttyS0) */
	int uart2 = open("/dev/ttyS1", O_RDWR | O_NONBLOCK | O_NOCTTY); //

	if (uart2 < 0) {
		printf("ERROR opening UART2, aborting..\n");
		return uart2;
	}

	struct termios uart2_config;

	struct termios uart2_config_original;

	int termios_state = 0;

	int ret;

	/* let the line settle */

	usleep(100000);

	/* Read the  buffer length */

	ioctl(uart2, FIONSPACE, (unsigned long)&uart2_buffer_size);


#define UART_BREAK_RUNTIME_CONF
#ifdef UART_BREAK_RUNTIME_CONF

	if ((termios_state = tcgetattr(uart2, &uart2_config)) < 0) {
		printf("ERROR getting termios config for UART2: %d\n", termios_state);
		ret = termios_state;
		goto cleanup;
	}

	memcpy(&uart2_config_original, &uart2_config, sizeof(struct termios));

	/* Set baud rate */
	if (cfsetispeed(&uart2_config, B9600) < 0 || cfsetospeed(&uart2_config, B9600) < 0) {
		printf("ERROR setting termios config for UART2: %d\n", termios_state);
		ret = ERROR;
		goto cleanup;
	}

	if ((termios_state = tcsetattr(uart2, TCSANOW, &uart2_config)) < 0) {
		printf("ERROR setting termios config for UART2\n");
		ret = termios_state;
		goto cleanup;
	}

	/* let the line settle */

	usleep(100000);

	/* Signal  on Console for rough timing */

	printf("1");
	fflush(stdout);

	/* Start Break */

	ioctl(uart2, TIOCSBRK, 0);
	usleep(250000);

	/* End Break */

	ioctl(uart2, TIOCCBRK, 0);

	/* Signal  on Console for rough timing */

	printf("0");
	fflush(stdout);

	/* let the line settle */

	usleep(100000);


#endif

	uint8_t sample_uart2[] = {'U', 'A', 'R', 'T', '2', ' ', '#', 0xff};

	int messages = uart2_buffer_size / sizeof(sample_uart2);
	messages = messages / 2;
	int i, r;

	for (i = 0; i < messages; i++) {
		/* uart2 -> */
		r = write(uart2, sample_uart2, sizeof(sample_uart2));

		if (r > 0) {
			uart2_nwrite0 += r;
		}
	}

	/* Ensure we are sending */

	usleep(100000);

	/* Signal  on Console for rough timing */

	printf("1");
	fflush(stdout);

	/* Start Break */

	ioctl(uart2, TIOCSBRK, 0);
	usleep(250000);

	/* End Break */

	ioctl(uart2, TIOCCBRK, 0);

	/* Signal  on Console for rough timing */

	printf("0");
	fflush(stdout);

	/* Begin writing again*/

	for (i = 0; i < messages; i++) {
		/* uart2 -> */
		r = write(uart2, sample_uart2, sizeof(sample_uart2));

		if (r > 0) {
			uart2_nwrite1 += r;
		}
	}

	int left = -1;
	int wait = 0;

	for (wait = 0; wait < 1000 && left != uart2_buffer_size;  wait++) {
		ioctl(uart2, FIONSPACE, (unsigned long)&left);
		usleep(250000);
	}

#define UART_BREAK_RUNTIME_CONF
#ifdef UART_BREAK_RUNTIME_CONF

	/* Set back to original settings */
	if ((termios_state = tcsetattr(uart2, TCSANOW, &uart2_config_original)) < 0) {
		printf("ERROR setting termios config for UART2\n");
		ret = termios_state;
		goto cleanup;
	}

#endif
	close(uart2);

	printf("uart2_buffer_size %d wait %d uart2_nwrite0 %d uart2_nwrite1 %d\n", uart2_buffer_size, wait, uart2_nwrite0,
	       uart2_nwrite1);

	return OK;
cleanup:
	close(uart2);
	return ret;

}