usb转串口异步读取数据

来源：互联网发布：网络cv设备编辑：程序博客网时间：2024/06/16 08:10

该实验是通过usb转串口线连接了开发板的 uart3和pc。

在pc上编译下面代码并执行

#include<stdio.h>#include <signal.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#define MODEMDEVICE "/dev/ttyUSB0"#define FALSE 0#define TRUE 1int wait_flag=TRUE;void signal_handler(int i){    printf("%s\n", __func__);    wait_flag=TRUE; }int main(){        int fd=0;    int res;    char buf[512]={0};    int STOP = 1;    fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY | O_NONBLOCK);            if (fd <0) {perror(MODEMDEVICE); return -1; }    signal(SIGIO, signal_handler);     /* allow the process to receive SIGIO */    fcntl( fd, F_SETOWN, getpid() );        int flags = fcntl( fd, F_GETFL );            fcntl( fd, F_SETFL, flags|FASYNC );        while(STOP){        if(wait_flag){            res = read(fd,buf,512);            buf[res]='\0';            printf("%d : %s\n", res, buf);            if(buf[0]=='s' && buf[1] =='t'){                STOP = 0;            }            wait_flag=FALSE;        }        //sleep(1);    }    printf("exit...\n");        close(fd);    return 0;}

执行效果：

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