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头文件:
#ifndef __SERIAL_H__
#define __SERIAL_H__
enum COMPORT
{
COM0 = 0,
COM1,
COM2,
COM3,
ttyUSB0,
ttyUSB1,
ttyUSB2
};
#ifdef __cplusplus
extern "C"{
#endif
//功能: 打开串口
//index 参考COMPORT
int serial_OpenPort(int index);
//功能：设置串口通信参数
//fd:打开串口后返回的文件句柄
//speed是波特率,参数如下：
//0:B2400;
//1:B4800;
//2:B9600;
//3:B19200;
//4:B38400;
//5:B57600;
//6:B115200;
//databits数据位:
//0:5位
//1:6位
//2:7位
//3:8位
//stopbits停止位:
//1:1位
//2:2位
//stopbits校验位:
//0:无校验
//1:奇校验
//2:偶校验
int serial_SetPara(int fd, int speed, int databits, int stopbits, int parity);
//功能:向串口发送数据
//fd:打开串口后返回的文件句柄
//data:已经分配好的缓冲数组,用于存放即将发送的串口数据
//datalength:缓冲区的数据长度
int serial_WriteData(int fd, const char *data, int datalength);
//功能: 读取串口数据
//fd:打开串口后返回的文件句柄
//data:已经分配好的缓冲数组,用于接收串口数据
//datalength:每次最多读取多少个字节
int serial_ReadData(int fd, unsigned char *data, int datalength);
//功能:关闭串口
//fd:打开串口后返回的文件句柄
void serial_ClosePort(int fd);
#ifdef __cplusplus
}
#endif
#endif源文件:
#include "serial.h"
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/signal.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <errno.h>
#include <limits.h>
#include <string.h>
int serial_BaudRate(int baudrate)
{
switch(baudrate)
{
case 0:
return (B2400);
case 1:
return (B4800);
case 2:
return (B9600);
case 3:
return (B19200);
case 4:
return (B38400);
case 5:
return (B57600);
case 6:
return (B115200);
default:
return (B9600);
}
}
int serial_SetPara(int serialfd, int speed, int databits, int stopbits, int parity)
{
struct termios termios_new;
bzero(&termios_new, sizeof(termios_new));//µÈŒÛÓÚmemset(&termios_new,sizeof(termios_new));
cfmakeraw(&termios_new);//ŸÍÊÇœ«ÖÕ¶ËÉèÖÃΪÔʌģʜ
termios_new.c_cflag = serial_BaudRate(speed);
termios_new.c_cflag |= CLOCAL | CREAD;
// termios_new.c_iflag = IGNPAR | IGNBRK;
termios_new.c_cflag &= ~CSIZE;
switch (databits)
{
case 0:
termios_new.c_cflag |= CS5;
break;
case 1:
termios_new.c_cflag |= CS6;
break;
case 2:
termios_new.c_cflag |= CS7;
break;
case 3:
termios_new.c_cflag |= CS8;
break;
default:
termios_new.c_cflag |= CS8;
break;
}
switch (parity)
{
case 0: //as no parity
termios_new.c_cflag &= ~PARENB; //Clear parity enable
// termios_new.c_iflag &= ~INPCK; /* Enable parity checking */ //add by fu
break;
case 1:
termios_new.c_cflag |= PARENB; // Enable parity
termios_new.c_cflag &= ~PARODD;
break;
case 2:
termios_new.c_cflag |= PARENB;
termios_new.c_cflag |= ~PARODD;
break;
default:
termios_new.c_cflag &= ~PARENB; // Clear parity enable
break;
}
switch (stopbits)// set Stop Bit
{
case 1:
termios_new.c_cflag &= ~CSTOPB;
break;
case 2:
termios_new.c_cflag |= CSTOPB;
break;
default:
termios_new.c_cflag &= ~CSTOPB;
break;
}
tcflush(serialfd, TCIFLUSH); // Çå³ýÊäÈ뻺Žæ
tcflush(serialfd, TCOFLUSH); // Çå³ýÊä³ö»ºŽæ
termios_new.c_cc[VTIME] = 1; // MINÓë TIME×éºÏÓÐÒÔÏÂËÄÖÖ£º1.MIN = 0 , TIME =0 ÓÐREADÁ¢ŒŽ»ØŽ« ·ñÔòŽ«»Ø 0 ,²»¶ÁÈ¡ÈκÎ×ÖÔª
termios_new.c_cc[VMIN] = 1; // 2¡¢ MIN = 0 , TIME >0 READ Ž«»Ø¶ÁµœµÄ×ÖÔª,»òÔÚÊ®·ÖÖ®Ò»ÃëºóŽ«»ØTIME ÈôÀŽ²»Œ°¶ÁµœÈκÎ×ÖÔª,ÔòŽ«»Ø0
tcflush (serialfd, TCIFLUSH); // 3¡¢ MIN > 0 , TIME =0 READ »áµÈŽý,Ö±µœMIN×ÖÔª¿É¶Á
return tcsetattr(serialfd, TCSANOW, &termios_new); // 4¡¢ MIN > 0 , TIME > 0 ÿһžñ×ÖÔªÖ®ŒäŒÆʱÆ÷ŒŽ»á±»Æô¶¯ READ »áÔÚ¶ÁµœMIN×ÖÔª,Ž«»ØÖµ»ò
}
int serial_WriteData(int fd,const char *data, int datalength )//index Žú±íŽ®¿ÚºÅ 0 Ž®¿Ú/dev/ttyAMA1 ......
{
if(fd < 0){ return -1;}
int len = 0, total_len = 0;//modify8.
for (total_len = 0; total_len < datalength;)
{
len = 0;
len = write(fd, &data[total_len], datalength - total_len);
printf("WriteData fd = %d ,len =%d,data = %s\n", fd, len, data);
if (len > 0)
{
total_len += len;
}
else if(len <= 0)
{
len = -1;
break;
}
}
return len;
}
int serial_ReadData(int fd,unsigned char *data, int datalength)
{
if(fd <0){ return -1;}
int len = 0;
memset(data, 0, datalength);
int max_fd = 0;
fd_set readset = {0};
struct timeval tv = {0};
FD_ZERO(&readset);
FD_SET((unsigned int)fd, &readset);
max_fd = fd + 1;
tv.tv_sec = 0;
tv.tv_usec = 1000;
if (select(max_fd, &readset, NULL, NULL, &tv) < 0)
{
printf("ReadData: select error\n");
}
int nRet = FD_ISSET(fd, &readset);
if (nRet)
{
len = read(fd, data, datalength);
}
return len;
}
void serial_ClosePort(int fd)
{
struct termios termios_old;
if(fd > 0)
{
tcsetattr(fd, TCSADRAIN, &termios_old);
::close (fd);
}
}
int serial_OpenPort(int index)
{
char *device;
switch(index)
{
case COM0: device="/dev/ttyAMA0"; break;
case COM1: device="/dev/ttyAMA1"; break;
case COM2: device="/dev/ttyAMA2"; break;
case COM3: device="/dev/ttyAMA3"; break;
case ttyUSB0: device="/dev/ttyUSB0"; break;
case ttyUSB1: device="/dev/ttyUSB1"; break;
case ttyUSB2: device="/dev/ttyUSB2"; break;
default: device="/dev/ttyAMA2"; break;
}
int fd = open(device, O_RDWR | O_NOCTTY | O_NONBLOCK);//O_RDWR | O_NOCTTY | O_NDELAY //O_NONBLOCK
if (fd < 0){
return -1;
}
struct termios termios_old;
tcgetattr(fd, &termios_old);
return fd;
}编译：
g++ serial.h serial.cpp -fPIC -shared -o libserial.so
