/*
* Set Baudrate
* 设置波特率，fd是打开设备节点的句柄
* */
int set_speed(int fd)
{
struct termios option;
struct termios old_option;
int i = 0;
//get the old option
tcgetattr(fd, &old_option);// termios是所要操作的结构体
for (i = 0; i < sizeof(speed_array)/sizeof(int); i++){
if(serial_port.serial_baud == name_array[i]){
tcflush(fd, TCIOFLUSH);
cfsetispeed(&option, speed_array[i]);
cfsetospeed(&option, speed_array[i]);
if(tcsetattr(fd, TCSANOW, &option) != 0){//配置立即生效
printf("set serial baudrate failed\n");
return ERROR;
}else{
tcflush(fd, TCIOFLUSH);//清空输入输出队列
if(DEBUG) printf("set serial baudrate sucessed\n");
return OK;
}
}
}
}
/*
* Set Other Paramters
*设置其他的参数
* */
int set_other_parm(int fd)
{
struct termios options;
struct termios old_options;
if(tcgetattr(fd, &old_options) != 0){
printf("Failed to getattr\n");
return ERROR;
}
options.c_cflag |= (CLOCAL|CREAD);
options.c_cflag &= ~CSIZE;
/*set Date Bits*/
switch (serial_port.data_bits){
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
options.c_cflag |= CS8;
break;
}
/*Set Parity Bites*/
switch (serial_port.parity){
case 'n':
case 'N':
options.c_cflag &= ~PARENB;
options.c_iflag &= ~INPCK;
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD|PARENB);
options.c_iflag |= INPCK;
break;
case 'e':
case 'E':
options.c_cflag |= PARENB;
options.c_cflag &= ~PARODD;
options.c_iflag |= INPCK;
break;
default:
options.c_cflag &= ~PARENB;
options.c_iflag &= ~INPCK;
break;
printf("default parity none parity\n");
}
/*Set Stop Bites*/
switch (serial_port.stop_bits){
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
options.c_cflag &= ~CSTOPB;
}
if(serial_port.parity != 'n' || serial_port.parity != 'N'){
options.c_iflag |= INPCK;
}
options.c_cc[VTIME] = 0;//Timeout parma 超时时间的设置
options.c_cc[VMIN] = 0;//read x bite return 读到多少个字节才进行操作，这里设置为0
options.c_iflag |= IGNPAR|ICRNL;
options.c_oflag |= OPOST;//原始模式，有两种模式，若不是原始模式的话，则会在\n后，才会输出
options.c_iflag &= ~(IXON|IXOFF|IXANY);
tcflush(fd, TCIFLUSH);
if(tcsetattr(fd, TCSANOW, &options) != 0){
printf("set serial other parma failed\n");
return ERROR;
}
return OK;
}
到这里，基本的参数就配置完毕了，这里需要注意VMIN和VTIME的配置和原始模式的配置。
接口写好了，写个测试的程序来进行测试就好，测试程序写的比较丑，见谅，哈哈：
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include "serial_port.h"
int main(int argc, char *argv[])
{
int ret;
int fd;
unsigned char data[50];
z_Serial_port serial_p;
printf("Configing serial from local file...\n");
ret = serial_config();
if(ret != 1){
printf("Failed to config serial\n");
return -1;
}
serial_p = get_current_serial();
fd = open(serial_p.serial_name,O_RDWR, 0);//以读写的方式打开
printf(".opening. %s\n", serial_p.serial_name);
if(fd == -1){
printf("Can't open tty\n");
return -1;
}
// set speed
if(set_speed(fd) < 0){
printf("set speed Failed\n");
return -1;
}
if(fcntl(fd, F_SETFL, O_NONBLOCK) < 0){
printf("fcntl failed\n");
return -1;
}
if(isatty(STDIN_FILENO)==0)
{
printf("not a terminal device\n");
}else
printf("isatty success!\n");
//set other parma like stopbites etc.
if(set_other_parm(fd) < 0 ){
printf("set other parm failed\n");
return -1;
}
//write data
int i;
char buff[512];
char buff21[] = "Hi Babby！";
int nread,nwrite = 0;
int nx;
printf("fd = %d\n",fd );
nx = write(fd,buff21,sizeof(buff21));