1、背景介紹

目前公司做的項目中使用了9344 USB轉串口芯片，這樣通過USB擴展四路串口，便于擴展。

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項目中CPU通過串口與CPLD進行數據傳輸，實現點燈和讀取機箱號、槽位號功能。

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2、驅動加載

X86目前安裝的linux操作系統，為了識別9344芯片，首先需要安裝驅動，驅動源碼下載地址：

https://download.csdn.net/download/jj12345jj198999/12244680

insmod?后就能在dev下看到四個串口設備

/dev/ttyWCHUSB0

/dev/ttyWCHUSB1

/dev/ttyWCHUSB2

/dev/ttyWCHUSB3

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3、應用示例

這里使用了串口與CPLD通信，實現點燈和讀機箱、槽位號功能，首先定義了傳輸規則，如下：

然后就可以編寫應用程序了，代碼如下：

/* TTY testing utility (using tty driver)* Copyright (c) 2020* This program is free software; you can redistribute it and/or modify* it under the terms of the GNU General Public License as published by* the Free Software Foundation; either version 2 of the License.** Cross-compile with cross-gcc -I /path/to/cross-kernel/include*/#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <fcntl.h> #include <termios.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <linux/serial.h> #include "uart.h"int speed_arr[] = {B115200,B57600,B38400,B19200,B9600,B4800,B2400,B1200,B300 };int name_arr[] = {115200,57600,38400,19200,9600,4800,2400,1200,300 };/*** 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 set** The function return 0 if success, or -1 if fail.*/ int libtty_setopt(int fd, int speed, int databits, int stopbits, char parity) {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 tty speed */for (i = 0; i < sizeof(speed_arr) / sizeof(int); i++) {if (speed == name_arr[i]) {cfsetispeed(&newtio, speed_arr[i]);cfsetospeed(&newtio, speed_arr[i]);}}/* 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\n");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\n");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\n");return -1;}newtio.c_cc[VTIME] = 0; /* Time-out value (tenths of a second) [!ICANON]. */newtio.c_cc[VMIN] = 0; /* Minimum number of bytes read at once [!ICANON]. */tcflush(fd, TCIOFLUSH);if (tcsetattr(fd, TCSANOW, &newtio) != 0){perror("tcsetattr");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.*/ int libtty_open(const char *devname) {int fd = open(devname, O_RDWR | O_NOCTTY | O_NDELAY);int flags = 0;if (fd == -1) {perror("open device failed");return -1;}flags = fcntl(fd, F_GETFL, 0);flags &= ~O_NONBLOCK;if (fcntl(fd, F_SETFL, flags) < 0) {printf("fcntl failed.\n");return -1;}if (isatty(fd) == 0){printf("not tty device.\n");return -1;}elseprintf("tty device test ok.\n");return fd; }/*** libtty_close - close tty device* @fd: the device handle**/ int libtty_close(int fd) {return close(fd); }void tty_test(int fd) {int nwrite, nread;char buf[10];int i;char hexarray[] = { 0xaa, 0x88, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x01, 0x55 };memset(buf, 0x55, sizeof(buf));while (1) {nwrite = write(fd, hexarray, sizeof(hexarray));printf("wrote %d bytes already.\n", nwrite);sleep(1);nread = read(fd, buf, sizeof(buf));printf("read %d bytes already.\n", nread);printf("*************************\n");for (i = 0; i < nread; i++)printf(" 0x%.2x", buf[i]);printf("\n*************************\n");sleep(1);} }int libtty_set_rs485(int fd, int enable) {struct serial_rs485 rs485conf;int ret;if (enable)rs485conf.flags |= SER_RS485_ENABLED;elsers485conf.flags &= ~SER_RS485_ENABLED;ret = ioctl(fd, TIOCSRS485, &rs485conf);if (ret < 0) {printf("set rs485 fail.\n");}return ret; }#if 0 int main(int argc, char *argv[]) {int fd;int ret;char ch;fd = libtty_open("/dev/ttyWCHUSB3");if (fd < 0) {printf("libtty_open error.\n");exit(0);}ret = libtty_setopt(fd, 9600, 8, 1, 'n');if (ret != 0) {printf("libtty_setopt error.\n");exit(0);}// enable rs485ret = libtty_set_rs485(fd, 1);if (ret != 0) {printf("libtty_set_rs485 error.\n");exit(0);}tty_test(fd);ret = libtty_close(fd);if (ret != 0) {printf("libtty_close error.\n");exit(0);} } #endifint led_on(int number) {int fd;int ret;char ch;int nwrite;char hexarray1[] = { 0xaa, 0x88, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };char hexarray2[] = { 0xaa, 0x88, 0x00, 0x01, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };char hexarray3[] = { 0xaa, 0x88, 0x00, 0x02, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };char hexarray4[] = { 0xaa, 0x88, 0x00, 0x03, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };char hexarray5[] = { 0xaa, 0x88, 0x00, 0x04, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };char hexarray6[] = { 0xaa, 0x88, 0x00, 0x05, 0x80, 0x00, 0x00, 0x00, 0x01, 0x55 };fd = libtty_open("/dev/ttyWCHUSB2");if (fd < 0) {printf("libtty_open error.\n");return -1;}ret = libtty_setopt(fd, 9600, 8, 1, 'n');if (ret != 0) {printf("libtty_setopt error.\n");return -1;}// enable rs485ret = libtty_set_rs485(fd, 1);if (ret != 0) {printf("libtty_set_rs485 error.\n");return -1;}switch(number){case 0:nwrite = write(fd, hexarray1, sizeof(hexarray1));break;case 1:nwrite = write(fd, hexarray2, sizeof(hexarray2));break;case 2:nwrite = write(fd, hexarray3, sizeof(hexarray3));break;case 3:nwrite = write(fd, hexarray4, sizeof(hexarray4));break;case 4:nwrite = write(fd, hexarray5, sizeof(hexarray5));break;case 5:nwrite = write(fd, hexarray6, sizeof(hexarray6));break;default:break;}ret = libtty_close(fd);if (ret != 0) {printf("libtty_close error.\n");return -1;}return 0; }int led_off(int number) {int fd;int ret;char ch;int nwrite;char hexarray1[] = { 0xaa, 0x88, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };char hexarray2[] = { 0xaa, 0x88, 0x00, 0x01, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };char hexarray3[] = { 0xaa, 0x88, 0x00, 0x02, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };char hexarray4[] = { 0xaa, 0x88, 0x00, 0x03, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };char hexarray5[] = { 0xaa, 0x88, 0x00, 0x04, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };char hexarray6[] = { 0xaa, 0x88, 0x00, 0x05, 0x80, 0x00, 0x00, 0x00, 0x00, 0x55 };fd = libtty_open("/dev/ttyWCHUSB2");if (fd < 0) {printf("libtty_open error.\n");return -1;}ret = libtty_setopt(fd, 9600, 8, 1, 'n');if (ret != 0) {printf("libtty_setopt error.\n");return -1;}// enable rs485ret = libtty_set_rs485(fd, 1);if (ret != 0) {printf("libtty_set_rs485 error.\n");return -1;}switch(number){case 0:nwrite = write(fd, hexarray1, sizeof(hexarray1));break;case 1:nwrite = write(fd, hexarray2, sizeof(hexarray2));break;case 2:nwrite = write(fd, hexarray3, sizeof(hexarray3));break;case 3:nwrite = write(fd, hexarray4, sizeof(hexarray4));break;case 4:nwrite = write(fd, hexarray5, sizeof(hexarray5));break;case 5:nwrite = write(fd, hexarray6, sizeof(hexarray6));break;default:break;}ret = libtty_close(fd);if (ret != 0) {printf("libtty_close error.\n");return -1;}return 0; }int get_chasis() {int fd;int ret;char ch;int nwrite, nread;char buf[10];char chasis_temp1,chasis_temp2;int chasis=0;int i;char hexarray[] = { 0xaa, 0x88, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55 };memset(buf, 0x55, sizeof(buf));fd = libtty_open("/dev/ttyWCHUSB4");if (fd < 0) {printf("libtty_open error.\n");return -1;}ret = libtty_setopt(fd, 9600, 8, 1, 'n');if (ret != 0) {printf("libtty_setopt error.\n");return -1;}// enable rs485ret = libtty_set_rs485(fd, 1);if (ret != 0) {printf("libtty_set_rs485 error.\n");return -1;}nwrite = write(fd, hexarray, sizeof(hexarray));sleep(1);nread = read(fd, buf, sizeof(buf));printf("read %d bytes already.\n", nread);chasis_temp1=buf[7];chasis_temp2=buf[8];chasis=((chasis_temp1<<8)|chasis_temp2)&0x3f;ret = libtty_close(fd);if (ret != 0) {printf("libtty_close error.\n");return -1;}return chasis; }int get_slot() {int fd;int ret;char ch;int nwrite, nread;char buf[10];char slot_temp1,slot_temp2;int slot=0;int i;char hexarray[] = { 0xaa, 0x88, 0x00, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55 };memset(buf, 0x55, sizeof(buf));fd = libtty_open("/dev/ttyWCHUSB3");if (fd < 0) {printf("libtty_open error.\n");return -1;}ret = libtty_setopt(fd, 9600, 8, 1, 'n');if (ret != 0) {printf("libtty_setopt error.\n");return -1;}// enable rs485ret = libtty_set_rs485(fd, 1);if (ret != 0) {printf("libtty_set_rs485 error.\n");return -1;}nwrite = write(fd, hexarray, sizeof(hexarray));sleep(1);nread = read(fd, buf, sizeof(buf));printf("read %d bytes already.\n", nread);slot_temp1=buf[7];slot_temp2=buf[8];slot=((slot_temp1<<8)|slot_temp2)&0x1f;ret = libtty_close(fd);if (ret != 0) {printf("libtty_close error.\n");return -1;}return slot; }

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總結

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