linux下串口控制

核心提示：databit = pportinfo -> databit;switch(databit){case '5':termios_new.c_cflag |= CS5;case '6':termios_new.c_cflag |= CS6;case '7':termi

databit = pportinfo -> databit;
switch(databit){
case '5':
termios_new.c_cflag |= CS5;
case '6':
termios_new.c_cflag |= CS6;
case '7':
termios_new.c_cflag |= CS7;
default:
termios_new.c_cflag |= CS8;
}
//控制模式 parity check
parity = pportinfo -> parity;
switch(parity){
case '0':{
termios_new.c_cflag &= ~PARENB; //no parity check
}break;
case '1':{
termios_new.c_cflag |= PARENB; //odd check
termios_new.c_cflag &= ~PARODD;
}break;
case '2':{
termios_new.c_cflag |= PARENB; //even check
termios_new.c_cflag |= PARODD;
}break;
}
//控制模式, stop bits
stopbit = pportinfo -> stopbit;
if(stopbit == '2'){
termios_new.c_cflag |= CSTOPB; //2 stop bits
}
else{
termios_new.c_cflag &= ~CSTOPB; //1 stop bits
}
//other attributions default
termios_new.c_oflag &= ~OPOST; //输出模式, 原始数据输出
termios_new.c_cc[VMIN] = 1; //控制字符, 所要读取字符的最小数量
termios_new.c_cc[VTIME] = 1; //控制字符, 读取第一个字符的等待时间, unit: (1/10)second
tcflush(fdcom, TCIFLUSH); //溢出的数据可以接收,但不读
tmp = tcsetattr(fdcom, TCSANOW, &termios_new); //设置新属性, TCSANOW: 所由改变立即生效
tcgetattr(fdcom, &termios_old);
return(tmp);
}
/*******************************************
* Open serial port
* tty: 端口号 ttyS0, ttyS1, ....
* 返回值为串口文件描述符
********************************************/
int PortOpen(pportinfo_t pportinfo)
{
int fdcom; //串口文件描述符
char *ptty;
ptty = get_ptty(pportinfo);
//fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK | O_NDELAY);
fdcom = open(ptty, O_RDWR | O_NOCTTY | O_NONBLOCK);
return (fdcom);
}
/*******************************************
* Close serial port
********************************************/
void PortClose(int fdcom)
{
close(fdcom);
}
/********************************************
* send data
* fdcom: 串口描述符, data: 待发送数据, datalen: 数据长度
* 返回实际发送长度
*********************************************/
int PortSend(int fdcom, char *data, int datalen)
{
int len = 0;
len = write(fdcom, data, datalen); //实际写入的长度
if(len == datalen){
return (len);
}
else{
tcflush(fdcom, TCOFLUSH);
return -1;
}
}
/*******************************************
* receive data
* 返回实际读入的字节数
*
********************************************/
int PortRecv(int fdcom, char *data, int datalen, int baudrate)
{
int readlen, fs_sel;
fd_set fs_read;
struct timeval tv_timeout;
FD_ZERO(&fs_read);
FD_SET(fdcom, &fs_read);
tv_timeout.tv_sec = TIMEOUT_SEC(datalen, baudrate);
tv_timeout.tv_usec = TIMEOUT_USEC;
fs_sel = select(fdcom+1, &fs_read, NULL, NULL, &tv_timeout);
if(fs_sel){
readlen = read(fdcom, data, datalen);
return(readlen);