imx6ul uart8路串口调试（代码）
uart这里的调试要注意的是管脚的功能配置，需要更改设备树文件；
更改设备树文件：https://blog.csdn.net/cao849861802/article/details/111604277
其他问题：这里是操作的232的配置，如果想做485的最好用硬件来直接做485，因为我这边用软件尝试了几次都未成功。
#include <stdio.h> //标准输入输出,如printf、scanf以及文件操作#include <stdlib.h> //标准库头文件，定义了五种类型、一些宏和通用工具函数#include <unistd.h> //定义 read write close lseek 等Unix标准函数#include <sys/types.h> //定义数据类型，如 ssiz e_t off_t 等#include <sys/stat.h> //文件状态#include <fcntl.h> //文件控制定义#include <termios.h> //终端I/O#include <errno.h> //与全局变量 errno 相关的定义#include <getopt.h> //处理命令行参数#include <string.h> //字符串操作#include <time.h> //时间#include <sys/select.h> //select函数#include <sys/ioctl.h>#include <net/if.h>#include <pthread.h>int uartfd[7];int setOpt(int fd, int nSpeed, int nBits, int nParity, int nStop){struct termios newtio, oldtio;// 保存测试现有串口参数设置，在这里如果串口号等出错，会有相关的出错信息if (tcgetattr(fd, &oldtio) != 0){perror("SetupSerial 1");return -1;}bzero(&newtio, sizeof(newtio)); //新termios参数清零newtio.c_cflag |= CLOCAL | CREAD; //CLOCAL--忽略 modem 控制线,本地连线, 不具数据机控制功能, CREAD--使能接收标志// 设置数据位数newtio.c_cflag &= ~CSIZE; //清数据位标志switch (nBits){case 7:newtio.c_cflag |= CS7;break;case 8:newtio.c_cflag |= CS8;break;default:fprintf(stderr, "Unsupported data size\n");return -1;}// 设置校验位switch (nParity){case 'o':case 'O': //奇校验newtio.c_cflag |= PARENB;newtio.c_cflag |= PARODD;newtio.c_iflag |= (INPCK | ISTRIP);break;case 'e':case 'E': //偶校验newtio.c_iflag |= (INPCK | ISTRIP);newtio.c_cflag |= PARENB;newtio.c_cflag &= ~PARODD;break;case 'n':case 'N': //无校验newtio.c_cflag &= ~PARENB;break;default:fprintf(stderr, "Unsupported parity\n");return -1;}// 设置停止位switch (nStop){case 1:newtio.c_cflag &= ~CSTOPB;break;case 2:newtio.c_cflag |= CSTOPB;break;default:fprintf(stderr,"Unsupported stop bits\n");return -1;}// 设置波特率 2400/4800/9600/19200/38400/57600/115200/230400switch (nSpeed){case 2400:cfsetispeed(&newtio, B2400);cfsetospeed(&newtio, B2400);break;case 4800:cfsetispeed(&newtio, B4800);cfsetospeed(&newtio, B4800);break;case 9600:cfsetispeed(&newtio, B9600);cfsetospeed(&newtio, B9600);break;case 19200:cfsetispeed(&newtio, B19200);cfsetospeed(&newtio, B19200);break;case 38400:cfsetispeed(&newtio, B38400);cfsetospeed(&newtio, B38400);break;case 57600:cfsetispeed(&newtio, B57600);cfsetospeed(&newtio, B57600);break;case 115200:cfsetispeed(&newtio, B115200);cfsetospeed(&newtio, B115200);break;case 230400:cfsetispeed(&newtio, B230400);cfsetospeed(&newtio, B230400);break;default:printf("\tSorry, Unsupported baud rate, set default 9600!\n\n");cfsetispeed(&newtio, B9600);cfsetospeed(&newtio, B9600);break;}// 设置read读取最小字节数和超时时间newtio.c_cc[VTIME] = 1; // 读取一个字符等待1*(1/10)snewtio.c_cc[VMIN] = 1; // 读取字符的最少个数为1tcflush(fd,TCIFLUSH); //清空缓冲区if (tcsetattr(fd, TCSANOW, &newtio) != 0) //激活新设置{perror("SetupSerial 3");return -1;}printf("Serial set done!\n");return 0;}void uartFdCreate(){int i = 0;int ret = 0;char buf[64];for(i = 0; i < 7; i++){memset(buf,0,sizeof(buf));sprintf(buf,"/dev/ttymxc%d",i+1);uartfd[i] = open(buf, O_RDWR | O_NOCTTY | O_NDELAY);if(uartfd[i] < 0){printf("%s open failed ret = %d\r\n",buf,uartfd[i]);uartfd[i] = -1;continue;}ret = fcntl(uartfd[i], F_SETFL, 0);if(ret < 0){printf("fcntl failed ret = %d\r\n",ret);close(uartfd[i]);uartfd[i] = -1;continue;}if (isatty(uartfd[i]) == 0){printf("standard input is not a terminal device\r\n");close(uartfd[i]);uartfd[i] = -1;continue;}if (setOpt(uartfd[i], 115200, 8, 'N', 1)== -1) //设置8位数据位、1位停止位、无校验{printf("Set opt Error\r\n");close(uartfd[i]);uartfd[i] = -1;continue;}tcflush(uartfd[i], TCIOFLUSH); //清掉串口缓存fcntl(uartfd[i], F_SETFL, 0); //串口阻塞printf("uart%d fd create ok,fd = %d\r\n",i+1,uartfd[i]);}}void *uartrecv(void *arg){int i = 0;unsigned int maxfd = 0;unsigned int ret = 0;struct timeval waittime;fd_set rfd;char buf[128];printf("uart recv task stat****\r\n");while(1){FD_ZERO(&rfd);for(i = 0; i < 7; i++){if(uartfd[i] != -1){FD_SET(uartfd[i],&rfd);if(maxfd < uartfd[i]){maxfd = uartfd[i];}}}waittime.tv_sec = 1;waittime.tv_usec = 0;ret = select(maxfd + 1,&rfd,NULL,NULL,&waittime);if(0 >= ret){continue;}for(i = 0; i < 7; i++){if(FD_ISSET(uartfd[i],&rfd)){memset(buf,0,sizeof(buf));read(uartfd[i],buf,sizeof(buf) - 1);printf("uart%d recv buf = %s\r\n",i+1,buf);}}}}void main(){int i = 0;int retlen = 0;char buf[128];pthread_t ntid;uartFdCreate();pthread_create(&ntid, NULL, uartrecv, NULL);while(1){for(i = 0 ; i < 7; i++){if(uartfd[i] != -1){memset(buf,0,sizeof(buf));sprintf(buf,"this is uart%d send date",i+ 1);retlen = write(uartfd[i],buf,strlen(buf));if(retlen != strlen(buf)){tcflush(uartfd[i],TCOFLUSH);}}}sleep(5);}}
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