嵌入式Linux开发过程中，进行Linux串口测试，需要针对串口进行回环测试

或者指定串口接收一定的数据

或者指定串口发送一定的数据

使用该测试用例很快验证硬件串口的稳定性和正确性。

使用代码连接如下

Linux串口测试例程，进行Linux串口测试，需要针对串口进行回环测试；或者指定串口接收一定的数据-嵌入式文档类资源-CSDN文库

这里提供一个很好的测试用例，具体使用

#收发数据测试：
./uart_app /dev/ttyS1 -b 115200 -rw 123asd -asc -l

#发数据测试：
./uart_app /dev/ttyS1 -b 115200 -w 123asd -asc -l

#收数据测试：
./uart_app /dev/ttyS1 -b 115200 -r -asc -l

#其他用法参考如下：

其他用法参考如下help说明：

后缀说明如下

         printf("       -asc: read to ascii\n");
         printf("       -b: set buadrate  + [bps]\n");
         printf("       [bps] 300 600 1200 2400 4800 9600 19200 38400 57600 115200\n");
         printf("       -n: write end add enter\n");
         printf("       -l: loop\n");
         printf("       -ms: write xx ms interval\n");
         printf("       -r: read only\n");
         printf("       -w: write only  + [context]\n");
         printf("       -rw: read write + [context]\n");
         printf("       -h: for help\n");
         printf("==================================================\n");

makefile

#!/bin/bash

CC=arm-linux-gnueabihf-gcc

${CC} uart_app.c -o uart_app

源码如下

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>
#include <stdlib.h>

int set_opt(int fd,int nSpeed, int nBits, char nEvent, int nStop)
{
    struct termios newtio,oldtio;
    if  ( tcgetattr( fd,&oldtio)  !=  0) 
    { 
        perror("SetupSerial 1");
        return -1;
    }
    bzero( &newtio, sizeof( newtio ) );
    newtio.c_cflag  |=  CLOCAL | CREAD; 
    newtio.c_cflag &= ~CSIZE; 

    switch( nBits )
    {
    case 7:
        newtio.c_cflag |= CS7;
        break;
    case 8:
        newtio.c_cflag |= CS8;
        break;
    }

    switch( nEvent )
    {
    case 'O':                     //奇校验
        newtio.c_cflag |= PARENB;
        newtio.c_cflag |= PARODD;
        newtio.c_iflag |= (INPCK | ISTRIP);
        break;
    case 'E':                     //偶校验
        newtio.c_iflag |= (INPCK | ISTRIP);
        newtio.c_cflag |= PARENB;
        newtio.c_cflag &= ~PARODD;
        break;
    case 'N':                    //无校验
        newtio.c_cflag &= ~PARENB;
        break;
    }

switch( nSpeed )
    {
    case 300:
        cfsetispeed(&newtio, B300);
        cfsetospeed(&newtio, B300);
        break;    
    case 600:
        cfsetispeed(&newtio, B600);
        cfsetospeed(&newtio, B600);
        break;        
    case 1200:
        cfsetispeed(&newtio, B1200);
        cfsetospeed(&newtio, B1200);
        break;            
    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;
    default:
        printf("sorry! [%d bps] is not support ,Set default 9600bps now!\n",nSpeed);
        cfsetispeed(&newtio, B9600);
        cfsetospeed(&newtio, B9600);
        break;
    }
    if( nStop == 1 )
    {
        newtio.c_cflag &=  ~CSTOPB;
    }
    else if ( nStop == 2 )
    {
        newtio.c_cflag |=  CSTOPB;
    }
    newtio.c_cc[VTIME]  = 0;
    newtio.c_cc[VMIN] = 0;
    tcflush(fd,TCIFLUSH);
    if((tcsetattr(fd,TCSANOW,&newtio))!=0)
    {
        perror("com set error");
        return -1;
    }
    printf("set done!\n");
    return 0;
}

int open_port(int fd,char *dev)
{
    //char *dev[]={"/dev/ttyO1","/dev/ttyO2","/dev/ttyO3"};
    long  vdisable;
   fd = open( dev, O_RDWR|O_NOCTTY); //open("/dev/tttyS0",O_RDWR | O_NOCTTY);  //O_NDELAY
        if (-1 == fd)
        {
            perror("Can't Open Serial Port");
            return(-1);
        }
        else 
        {
            printf("open %s ok\n",dev);
        }
    
    if(fcntl(fd, F_SETFL, 0)<0)
    {
        printf("fcntl failed!\n");
    }
    else
    {
        printf("fcntl=%d\n",fcntl(fd, F_SETFL,0));
    }
    if(isatty(STDIN_FILENO)==0)
    {
        printf("standard input is not a terminal device\n");
    }
    else
    {
        printf("isatty success!\n");
    }
    printf("fd-open=%d\n",fd);
    return fd;
}

void msdelay(int val){
    while(val--)usleep(1000);
}

//#define DEBUG_STR  "ttySC1 554433"
#define Mode_W    1
#define Mode_R    2
#define Mode_RW   3
#define Version   "V1.1"
//const char *default_str = "hello serial test";
int main(int argc ,char **argv)
{
    int fd;
    int nread,i;
    char buff[1024];
    int nwrite;
    int setmode;
    char *wchr;
    int format = 0;
    int boudrate = 9600;
    int enter = 0;
    int loop = 0;
    int intervalMS = 1000;
    printf("\n==================================================\n");
    //printf("argc = %d\n",argc);
    if((argc < 2) || (!strcmp(argv[1],"-h"))||(!strcmp(argv[1],"help"))){
         printf("Version %s\n",Version);
         printf("[device] [option1] [option2] ....[optionN]\n");
         printf("option:\n");
         printf("       -asc: read to ascii\n");
         printf("       -b: set buadrate  + [bps]\n");
         printf("       [bps] 300 600 1200 2400 4800 9600 19200 38400 57600 115200\n");
         printf("       -n: write end add enter\n");
         printf("       -l: loop\n");
         printf("       -ms: write xx ms interval\n");
         printf("       -r: read only\n");
         printf("       -w: write only  + [context]\n");
         printf("       -rw: read write + [context]\n");
         printf("       -h: for help\n");
         printf("==================================================\n");
         return 1;
    }
    printf("Device [%s] \n",argv[1]);
    //------------------------------------------------------------
    for(i = 1; i < argc; i ++){
        if(!strcmp(argv[i],"-asc")){
            format = 1;
            printf("format ascii\n");
        }else if(!strcmp(argv[i],"-hex")){
            format = 0;
            printf("format hex\n");
        }    
        else if(!strcmp(argv[i],"-b")){
            i++;
            boudrate = atoi(argv[i]);
        }
        else if(!strcmp(argv[i],"-n")){
            enter = 1;
            printf("enter true\n");
        }
        else if(!strcmp(argv[i],"-l")){
            loop = 1;
            printf("loop true\n");
        }
        else if(!strcmp(argv[i],"-ms")){
            i++;
            intervalMS = atoi(argv[i]);
        }
        else if(!strcmp(argv[i],"-w")){    
            i++;
            setmode = Mode_W;
            wchr = (char*)argv[i];
            printf("write only  w:%s\n",wchr);
        }    
        else if(!strcmp(argv[i],"-r")){
            printf("read only\n");
            setmode = Mode_R;
        }    
        else if(!strcmp(argv[i],"-rw")){
            i++;
            setmode = Mode_RW;
            wchr = (char*)argv[i];
            printf("read write w:%s\n",wchr);
        }        
    }
    printf("boudrate = %d\n",boudrate);
    printf("interval : %d ms\n",intervalMS);
    printf("==================================================\n");
    if((fd=open_port(fd,argv[1]))<0){
        perror("open_port error");
        return;
    }
    if((i=set_opt(fd,boudrate,8,'N',1))<0){
        perror("set_opt error");
        return;
    }
    while(loop){
        switch(setmode){
            case Mode_W:
                nwrite = sprintf(buff,"%s",wchr);
                if(enter){
                    buff[nwrite++] = 0x0d;
                    buff[nwrite++] = 0x0a;
                }
                write(fd,buff,nwrite);
                printf("%s write :%s\n",argv[1],wchr);
                break;
            case Mode_R:
                nread=read(fd,buff,sizeof(buff));
                if(nread>0){
                    printf("\n%s read=%d : ",argv[1],nread);
                    if(format==0){
                        for(i = 0; i < nread;i++){
                            printf("%02x ",buff[i]);
                        }
                        printf("\n");
                    }else{
                        buff[nread] = '\0';
                        printf("%s\n",buff);
                    }
                }
                break;
            case Mode_RW:
                nwrite = sprintf(buff,"%s",wchr);
                if(enter){
                    buff[nwrite++] = 0x0d;
                    buff[nwrite++] = 0x0a;
                }
                write(fd,buff,nwrite);
                printf("%s write :%s\n",argv[1],wchr);
                //sleep(1);
                nread=read(fd,buff,sizeof(buff));
                if(nread>0){
                    printf("\n%s read=%d : ",argv[1],nread);
                    if(format==0){
                        for(i = 0; i < nread;i++){
                            printf("%02x ",buff[i]);
                        }
                        printf("\n");
                    }else{
                        buff[nread] = '\0';
                        printf("%s\n",buff);
                    }
                }        
                break;
            
        }
        //sleep(1);
        msdelay(intervalMS);
    }
    close(fd);
    return;
}

添加个代码封面