1、說明

本文針對Linux系統(tǒng)上如何對各類串口硬件進行出廠測試進行硬件連接和軟件使用說明，提供的軟件測試工具wchsertest，適用于USB、PCI、PCIe轉串口設備等、同樣也適用于原生ttyS串口。

2、串口測試硬件連接

在測試前，需要制作單獨的硬件治具，按下表連接信號線：

引腳連接示意圖：

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3、軟件使用方法

（1）插入待測試USB/PCI/PCIe轉串口設備。

（2）以CH342F（USB轉2串口芯片）為例，安裝對應VCP廠商驅動程序，進入/dev目錄查看出現如下設備節(jié)點：

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以CH382為例，安裝對應VCP廠商驅動程序，進入/dev目錄查看出現如下設備節(jié)點：

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（3）運行軟件，輸入命令格式：

./[可執(zhí)行文件] –D [設備節(jié)點路徑]

實例1（測試CH342的UART0）：sudo ./serial_port_test -D /dev/ttyCH343USB0

實例2（測試CH382的UART0）：sudo ./serial_port_test -D /dev/ttyWCH0

4、測試錯誤碼說明

根據輸出的錯誤碼和終端輸出信息可判斷故障信號線，下表為錯誤碼和說明。

5、測試實例

（1）測試成功實例

軟件分別以2400bps、9600bps、115200bps各測試一次。

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（2）測試錯誤實例

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根據輸出信息可知，DTR—DSR信號通訊存在錯誤，錯誤碼：0。

6、wchsertest工具源碼

/*
 * serial port factory test utility.
 *
 * Copyright (C) 2023 Nanjing Qinheng Microelectronics Co., Ltd.
 * Web:     http://wch.cn
 * Author:  WCH 

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#define termios asmtermios
#include 
#undef termios
#include 

#define DTR_ON	    1
#define DTR_OFF	    0
#define RTS_ON	    1
#define RTS_OFF	    0
#define BUF_SIZE    64
#define DTR_ON_CMD  0x0
#define DTR_OFF_CMD 0x1
#define RTS_ON_CMD  0x2
#define RTS_OFF_CMD 0x3

extern int ioctl(int d, int request, ...);

static const char *device = "/dev/ttyCH343USB0";
static int hardflow = 0;
static int verbose = 0;
static FILE *fp;

static const struct option lopts[] = {
	{ "device", required_argument, 0, 'D' },
	{ NULL, 0, 0, 0 },
};

static void print_usage(const char *prog)
{
	printf("Usage: %s [-DSvf]
", prog);
	puts("  -D --device    tty device to use
");
	exit(1);
}

static void parse_opts(int argc, char *argv[])
{
	int c;

	while (1) {
		c = getopt_long(argc, argv, "D:S:h", lopts, NULL);
		if (c == -1) {
			break;
		}
		switch (c) {
		case 'D':
			if (optarg != NULL)
				device = optarg;
			break;
		case 'h':
		default:
			print_usage(argv[0]);
			break;
		}
	}
}

/**
 * libtty_setcustombaudrate - set baud rate of tty device
 * @fd: device handle
 * @speed: baud rate to set
 *
 * The function return 0 if success, or -1 if fail.
 */
static int libtty_setcustombaudrate(int fd, int baudrate)
{
	struct termios2 tio;

	if (ioctl(fd, TCGETS2, &tio)) {
		perror("TCGETS2");
		return -1;
	}

	tio.c_cflag &= ~CBAUD;
	tio.c_cflag |= BOTHER;
	tio.c_ispeed = baudrate;
	tio.c_ospeed = baudrate;

	if (ioctl(fd, TCSETS2, &tio)) {
		perror("TCSETS2");
		return -1;
	}

	if (ioctl(fd, TCGETS2, &tio)) {
		perror("TCGETS2");
		return -1;
	}

	return 0;
}

/**
 * libtty_setopt - config tty device
 * @fd: device handle
 * @speed: baud rate to set
 * @databits: data bits to set
 * @stopbits: stop bits to set
 * @parity: parity to set
 * @hardflow: hardflow to set
 *
 * The function return 0 if success, or -1 if fail.
 */
static int libtty_setopt(int fd, int speed, int databits, int stopbits, char parity, char hardflow)
{
	struct termios newtio;
	struct termios oldtio;
	int i;

	bzero(&newtio, sizeof(newtio));
	bzero(&oldtio, sizeof(oldtio));

	if (tcgetattr(fd, &oldtio) != 0) {
		perror("tcgetattr");
		return -1;
	}
	newtio.c_cflag |= CLOCAL | CREAD;
	newtio.c_cflag &= ~CSIZE;

	/* set data bits */
	switch (databits) {
	case 5:
		newtio.c_cflag |= CS5;
		break;
	case 6:
		newtio.c_cflag |= CS6;
		break;
	case 7:
		newtio.c_cflag |= CS7;
		break;
	case 8:
		newtio.c_cflag |= CS8;
		break;
	default:
		fprintf(stderr, "unsupported data size
");
		return -1;
	}

	/* set parity */
	switch (parity) {
	case 'n':
	case 'N':
		newtio.c_cflag &= ~PARENB; /* Clear parity enable */
		newtio.c_iflag &= ~INPCK;  /* Disable input parity check */
		break;
	case 'o':
	case 'O':
		newtio.c_cflag |= (PARODD | PARENB); /* Odd parity instead of even */
		newtio.c_iflag |= INPCK;	     /* Enable input parity check */
		break;
	case 'e':
	case 'E':
		newtio.c_cflag |= PARENB;  /* Enable parity */
		newtio.c_cflag &= ~PARODD; /* Even parity instead of odd */
		newtio.c_iflag |= INPCK;   /* Enable input parity check */
		break;
	default:
		fprintf(stderr, "unsupported parity
");
		return -1;
	}

	/* set stop bits */
	switch (stopbits) {
	case 1:
		newtio.c_cflag &= ~CSTOPB;
		break;
	case 2:
		newtio.c_cflag |= CSTOPB;
		break;
	default:
		perror("unsupported stop bits
");
		return -1;
	}

	if (hardflow)
		newtio.c_cflag |= CRTSCTS;
	else
		newtio.c_cflag &= ~CRTSCTS;

	newtio.c_cc[VTIME] = 10; /* Time-out value (tenths of a second) [!ICANON]. */
	newtio.c_cc[VMIN] = 64; /* Minimum number of bytes read at once [!ICANON]. */

	tcflush(fd, TCIOFLUSH);

	if (tcsetattr(fd, TCSANOW, &newtio) != 0) {
		perror("tcsetattr");
		return -1;
	}

	/* set tty speed */
	if (libtty_setcustombaudrate(fd, speed) != 0) {
		perror("setbaudrate");
		return -1;
	}

	return 0;
}

/**
 * libtty_open - open tty device
 * @devname: the device name to open
 *
 * In this demo device is opened blocked, you could modify it at will.
 */
static int libtty_open(const char *devname)
{
	int fd = open(devname, O_RDWR | O_NOCTTY);
	int flags = 0;

	if (fd < 0) {
		perror("open device failed");
		return -1;
	}

	if (fcntl(fd, F_SETFL, 0) < 0) {
		printf("fcntl failed.
");
		return -1;
	}

	if (isatty(fd) == 0) {
		printf("not tty device.
");
		return -1;
	}

	return fd;
}

/**
 * libtty_close - close tty device
 * @fd: the device handle
 *
 * The function return 0 if success, others if fail.
 */
static int libtty_close(int fd)
{
	return close(fd);
}

/**
 * libtty_tiocmset - modem set
 * @fd: file descriptor of tty device
 * @bDTR: 0 on inactive, other on DTR active
 * @bRTS: 0 on inactive, other on RTS active
 *
 * The function return 0 if success, others if fail.
 */
static int libtty_tiocmset(int fd, char bDTR, char bRTS)
{
	unsigned long controlbits = 0;

	if (bDTR)
		controlbits |= TIOCM_DTR;
	if (bRTS)
		controlbits |= TIOCM_RTS;

	return ioctl(fd, TIOCMSET, &controlbits);
}

/**
 * libtty_tiocmget - modem get
 * @fd: file descriptor of tty device
 * @modembits: pointer to modem status
 *
 * The function return 0 if success, others if fail.
 */
static int libtty_tiocmget_check(int fd, unsigned long *modembits, int cmd)
{
	int ret = 0;

	ret = ioctl(fd, TIOCMGET, modembits);
	if (ret == 0) {
		switch (cmd) {
		case DTR_OFF_CMD: // DTR--DSR/DCD
			if ((*modembits & TIOCM_DSR) != 0) {
				printf("[error code: %d] DTR--DSR ERROR
", 0);
				ret = -1;
			}
			if ((*modembits & TIOCM_CD) != 0) {
				printf("[error code: %d] DTR--DCD ERROR
", 1);
				ret = -1;
			}
			break;
		case DTR_ON_CMD:
			if ((*modembits & TIOCM_DSR) == 0) {
				printf("[error code: %d] DTR--DSR ERROR
", 0);
				ret = -1;
			}
			if ((*modembits & TIOCM_CD) == 0) {
				printf("[error code: %d] DTR--DCD ERROR
", 1);
				ret = -1;
			}
			break;
		case RTS_OFF_CMD: // RTS--CTS/RI
			if ((*modembits & TIOCM_CTS) != 0) {
				printf("[error code: %d] RTS--CTS ERROR
", 2);
				ret = -1;
			}
			if ((*modembits & TIOCM_RI) != 0) {
				printf("[error code: %d] RTS--RI ERROR
", 3);
				ret = -1;
			}
			break;
		case RTS_ON_CMD:
			if ((*modembits & TIOCM_CTS) == 0) {
				printf("[error code: %d] RTS--CTS ERROR
", 2);
				ret = -1;
			}
			if ((*modembits & TIOCM_RI) == 0) {
				printf("[error code: %d] RTS--RI ERROR
", 3);
				ret = -1;
			}
			break;
		default:
			break;
		}
	}
	return ret;
}

static void sig_handler(int signo)
{
	printf("capture sign no:%d
", signo);
	if (fp != NULL) {
		fflush(fp);
		fsync(fileno(fp));
		fclose(fp);
	}
	exit(0);
}

void start_test(int fd)
{
	int ret, i, times, num, nwrite, nread, len;
	int len_w, pos_w, ret1, ret2, ret3;
	int total = 0, off_w, off_r;
	char c;
	unsigned long modemstatus;
	unsigned char buf_write[BUF_SIZE];
	unsigned char buf_read[BUF_SIZE];

	memset(buf_write, 0x00, BUF_SIZE);
	memset(buf_read, 0x00, BUF_SIZE);

	for (times = 0; times < 64; times++) {
		for (i = 0; i < BUF_SIZE; i++)
			buf_write[i] = i + BUF_SIZE * (times % 4);

		/* Send 64 bytes */
        off_w = 0;
        len = BUF_SIZE;
        while (len > 0) {
            nwrite = write(fd, buf_write + off_w, len);
            if (nwrite < 0) {
                perror("write");
                exit(1);
            }
            off_w += nwrite;
            len -= nwrite;
        }
        
		/* Receive and judge */
        off_r = 0;
		while (nwrite > 0) {
			nread = read(fd, buf_read + off_r, nwrite);
            if (nread < 0) {
                printf("read error!
");
				exit(1);
            }
            off_r += nread;
            nwrite -= nread;
		}

		total += nread;

		/* compare the buffer contents */
		if (memcmp(buf_read, buf_write, BUF_SIZE) != 0) {
			printf("[error code: %d] TXD/RXD test error
", 4);
			goto exit;
		}
	}
	printf("TXD/RXD test passed
");

	/* Set DTR invalid */
	if (libtty_tiocmset(fd, DTR_OFF, RTS_OFF) != 0)
		goto exit;
	usleep(10000);
	ret1 = libtty_tiocmget_check(fd, &modemstatus, DTR_OFF_CMD);

	/* Set DTR valid */
	if (libtty_tiocmset(fd, DTR_ON, RTS_OFF) != 0)
		goto exit;
	usleep(10000);
	ret2 = libtty_tiocmget_check(fd, &modemstatus, DTR_ON_CMD);

	/* Set RTS valid */
	if (libtty_tiocmset(fd, DTR_OFF, RTS_ON) != 0)
		goto exit;
	usleep(10000);
	ret3 = libtty_tiocmget_check(fd, &modemstatus, RTS_ON_CMD);

	if ((ret1 || ret2 || ret3) == 0)
		printf("DTR/RTS/DSR/CTS/DCD/RI test passed
");
	printf("
");

exit:
	return;
}

int main(int argc, char *argv[])
{
	int fd, ret, i, num, nwrite, nread;
	int len_w, pos_w, ret1, ret2, ret3, ret4;
	int total = 0, off = 0;
	char c;
	unsigned long modemstatus;
	unsigned char buf_write[BUF_SIZE];
	unsigned char buf_read[BUF_SIZE];

	parse_opts(argc, argv);
	signal(SIGINT, sig_handler);

	fd = libtty_open(device);
	if (fd < 0) {
		printf("libtty_open: %s error.
", device);
		exit(0);
	}

	/* 2400bps test */
	ret = libtty_setopt(fd, 2400, 8, 1, 'n', hardflow);
	if (ret != 0) {
		printf("libtty_setopt error.
");
		exit(0);
	}
	start_test(fd);

	/* 9600bps test */
	ret = libtty_setopt(fd, 9600, 8, 1, 'n', hardflow);
	if (ret != 0) {
		printf("libtty_setopt error.
");
		exit(0);
	}
	start_test(fd);

	/* 115200bps test */
	ret = libtty_setopt(fd, 115200, 8, 1, 'n', hardflow);
	if (ret != 0) {
		printf("libtty_setopt error.
");
		exit(0);
	}
	start_test(fd);

	ret = libtty_close(fd);
	if (ret != 0) {
		printf("libtty_close error.
");
		exit(0);
	}

	return 0;
}

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