嵌入式Linux下串口编程(一)
嵌入式Linux下串口编程(一)
| 嵌入式Linux下串口编程 一、配置内核 在嵌入式Linux下进行串口编程之前，先在内核中配置串口部分，如下：
二、应用程序 C文件： uart_init.c:打开设备、初始化串口(设置参数) main.c:测试串口读写 头文件： uart_init.h Makfile
uart_init.c #include <stdio.h> #include <stdlib.h> #include <string.h> #include <error.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #include <termios.h>
int open_termios(char *dev) { int fd = -1; if(-1 == (fd = open(dev,O_RDWR|O_NOCTTY|O_NONBLOCK))) { printf("open termios error!/n"); } return fd; }
int set_termios(int fd,long speed,char databit,char stopbit,char oebit) { struct termios newtio; int err = -1;
//清零结构体 bzero(&newtio,sizeof(newtio)); //设置接收使能 newtio.c_cflag |= CLOCAL | CREAD; // 设置数据位 switch(databit) { case 7: newtio.c_cflag |= CS7; break; case 8: newtio.c_cflag |= CS8; break; default: newtio.c_cflag |= CS8; break; } //设置停止位 switch(stopbit) { case 1: newtio.c_cflag &= ~CSTOPB; break; case 2: newtio.c_cflag |= CSTOPB; break; default: newtio.c_cflag &= ~CSTOPB; break; } //设置校验位 switch(oebit) { case 'O': //奇校验 newtio.c_cflag |= PARENB; newtio.c_cflag |= (INPCK | ISTRIP); newtio.c_cflag |= PARODD; break; case 'E': //偶数 newtio.c_cflag |= PARENB; newtio.c_cflag |= (INPCK | ISTRIP); newtio.c_cflag &= ~PARODD; break; case 'N': //不校验 newtio.c_cflag &= ~PARODD; break; default: //不校验 newtio.c_cflag &= ~PARODD; break; } //设置波特率 switch(speed) { 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 57600: cfsetispeed(&newtio,B57600); cfsetospeed(&newtio,B57600); break; case 115200: cfsetispeed(&newtio,B115200); cfsetospeed(&newtio,B115200); break; default: cfsetispeed(&newtio,B9600); cfsetospeed(&newtio,B9600); break; } //设置等待时间和最小接收字符数 newtio.c_cc[VTIME] = 0; newtio.c_cc[VMIN] = 0; //处理未接收字符 tcflush(fd,TCIFLUSH); //激活配置 if((tcsetattr(fd,TCSANOW,&newtio)) != 0) perror("com set error!"); else err = 0; perror("com set done!"); return err; }
uart_init.h #ifndef __UART_INIT__ #define __UART_INIT__ extern int open_termios(char *dev); int set_termios(int fd,long speed,char databit,char stopbit,char oebit); #endif
main.c #include <stdio.h> #include <stdlib.h> #include <error.h> #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <termios.h> #include "uart_init.h"
char *uart0_dev="/dev/ttySAC0";
int main(void) { int uart0_fd; int err = 0; char uart0_byte = 0; char *uart0_buff[8]={0};
uart0_fd = open_termios(uart0_dev); if(uart0_fd < 0) { exit(1); } do { err = set_termios(uart0_fd,115200,8,1,'N'); } while(-1 == err); while(1) { read(uart0_fd,&uart0_byte,1); if(0xfd == uart0_byte) { read(uart0_fd,uart0_buff,8); write(uart0_fd,uart0_buff,8); memset(uart0_buff,0,sizeof(uart0_buff)); uart0_byte = 0; }
} exit(0); }
Makefile #You can add source code file like the following SOURCE += main.c SOURCE += uart_init.c
##You can add header code file like the following HEADER += uart_init.h
#You can name the executable file like the following TARGET = UART_ARM
#You can add include path like the following INCLUDEPATH = #You can library path like the following LIBPATH = #You can add library like the following LIBS = -lpthread
#You cant add compile options like the following OPTION += -Wall OPTION += -g
#You can specify the compiler CC=arm-linux-gcc
#Don't modify the following code unless you know howto exactly OBJECTS =$(SOURCE:%.c=%.o)
$(TARGET):$(OBJECTS) $(CC) $(OPTION) $(INCLUDEPATH) $(LIBPATH) $(LIBS) -o $(TARGET) $(OBJECTS) clean: -rm -f $(TARGET) *.o *~ 在串口调试助手选择波特率，选择十六进制显示并打开串口后，发送“fd 31 32 33 34 35 36 37 38”这串十六进制数据后，接收端就出现“31 32 33 34 35 36 37 38”数据。 |