Linux下串口设置问题急！！

etual1983

Linux下串口设置问题急！！ [复制链接]

我在Linux下编写了一段串口程序，进行数据收发，程序如下：
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include

char xCal_crc(char *ptr,int len);
int fd;

#define _POSIX_SOURCE 1 /*符合POSIX标准的代码*/

int main( int argc, char **argv)
{
speed_t BAUDRATE = B115200;    /*定义串口速率，前面加个B然后是你所需要的速率。*/
char *MODEMDEVICE = "/dev/ttyS0"; /*使用COM1进行通讯*/
int res,i;
struct termios oldios,newios,opt;
char buff[10240];
char ACK[5],DAT[1024];
char *ptr = buff, *ptr2 = buff;

fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY  |  O_NONBLOCK ); /*以读写方式打开串口。使用不要MODEM的直接连接方式。 */
// fd = open(MODEMDEVICE, O_RDWR | O_NOCTTY  ); /*以读写方式打开串口。使用不要MODEM的直接连接方式。 */
if (fd < 0) {
perror(MODEMDEVICE);
printf("open uart error!\n");
exit(0);
}
tcgetattr(fd,&oldios); /*保存当前串口设置*/
bzero(&newios,sizeof(newios)); /*清空当前串口设置*/

/*设置无奇偶校验8N1*/
newios.c_cflag &= ~CSIZE;
newios.c_cflag |= CS8;
newios.c_cflag &= ~PARENB;
newios.c_cflag &= ~CSTOPB;
newios.c_cflag |= CS8;
/*终端为本地连接，忽略MODEM的状态线*/
newios.c_cflag |= CLOCAL;
newios.c_cflag |= CREAD;
/*设置非加工方式输入*/
newios.c_iflag |= IGNPAR;
newios.c_lflag &= ~( ICANON | ECHO | ISIG | IEXTEN | ECHOE );
newios.c_iflag &= ~INPCK;
newios.c_iflag &= ~ICRNL;
newios.c_iflag &= ~INLCR;
newios.c_iflag &= ~ISTRIP;
newios.c_iflag &= ~IXON;
newios.c_iflag &= ~BRKINT;
/*设置非加工方式输出*/
newios.c_oflag &= ~OPOST;
/*设置波特率*/
cfsetispeed( &newios, BAUDRATE );
cfsetospeed( &newios, BAUDRATE );
/*设置阻塞字节数和等待时间*/
newios.c_cc[VMIN] = 128;
newios.c_cc[VTIME] = 2;

tcflush(fd,TCIFLUSH);
tcsetattr(fd,TCSANOW,&newios); /*使端口属性设置生效*/
printf("seted !\n");

int once_read = 0, totle_num = 0, send_num = 0,j;
char crc;
send_num = 0;
struct timeval tpstart,tpend,a,b;
float timeuse,wait_val;
gettimeofday(&tpstart,NULL);
for( j=0; j<2000; j++ ){
ptr = buff;
ptr2 = buff;
once_read = 0;
send_num = 0;
gettimeofday(&a,NULL);
while(1){
once_read = read(fd, ptr, 1024);
if( once_read != -1 ){
send_num += once_read;
totle_num += once_read;
ptr += once_read;
}
if( send_num >= 1024 )
break;
}
gettimeofday(&b,NULL);
wait_val=1000000*(b.tv_sec-a.tv_sec)+b.tv_usec-a.tv_usec;
wait_val/=1000000;
printf("ACK Used Time:%f\n",wait_val);
for( i=0; i<1024; i++ ){
DAT = ptr2;
}
crc = xCal_crc( DAT, 1024 );
if( crc != 0x00 )
ACK[0] = 0x00;
   ACK[0] = DAT[1022] +1;
for( i=1; i<4; i++ )
ACK = 0xFF;
crc = xCal_crc( ACK, 4 );
ACK[4] = crc;
write( fd, ACK, 5 );
for( i=0; i<5; i++ ){
printf("%X",ACK);
}
printf("\n");
}
gettimeofday(&tpend,NULL);
timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+tpend.tv_usec-tpstart.tv_usec;
timeuse/=1000000;
printf("Used Time:%f\n",timeuse);
      tcsetattr(fd,TCSANOW,&oldios); /*使端口属性设置恢复*/
}

我设的波特率是115200，但是实际测的结果是读1K字节的时间差不多在0.09s左右，实际传输速度只有10K，和我设的波特率差距很大，不知道是怎么回事？
请高人指点一下吧！
急！

lifewing

115200bps = 14400Bps

wonter

pc机程序

/**************************************************
* Serial communication between PC and 51 board
*
* function: A running hores controlled by PC
* send one byte data to 51 board every one
* second
*
* compile: gcc -o main main.c
* eviroment: ubuntu 7.10
* compiler: gcc
*
* baud: 1200
* parit: N
* databits: 8
* stopbit: 1
***************************************************/
#include /*鏍囧噯杈撳叆杈撳嚭瀹氫箟*/
#include /*鏍囧噯鍑芥暟搴撳畾涔?/
#include /*Unix 鏍囧噯鍑芥暟瀹氫箟*/
#include
#include
#include /*鏂囦欢鎺у埗瀹氫箟*/
#include /*PPSIX 缁堢?鎺у埗瀹氫箟*/
#include /*閿欒?鍙峰畾涔?/
#define FALSE -1
#define TRUE 0
struct termio
{ unsigned short c_iflag; /* 杈撳叆妯″紡鏍囧織 */
unsigned short c_oflag; /* 杈撳嚭妯″紡鏍囧織 */
unsigned short c_cflag; /* 鎺у埗妯″紡鏍囧織*/
unsigned short c_lflag; /* local mode flags */
unsigned char c_line; /* line discipline */
unsigned char c_cc[NCCS]; /* control characters */
};
/**
* *@brief 璁剧疆涓插彛閫氫俊閫熺巼
* *@param fd 绫诲瀷 int 鎵撳紑涓插彛鐨勬枃浠跺彞鏌?
* *@param speed 绫诲瀷 int 涓插彛閫熷害
* *@return void
* */
int speed_arr[] = { B38400, B19200, B9600, B4800, B2400, B1200, B300,
B38400, B19200, B9600, B4800, B2400, B1200, B300, };
int name_arr[] = {38400, 19200, 9600, 4800, 2400, 1200, 300, 38400,
19200, 9600, 4800, 2400, 1200, 300, };
void set_speed(int fd, int speed){
int i;
int status;
struct termios Opt;
tcgetattr(fd, &Opt);
for ( i= 0; i < sizeof(speed_arr) / sizeof(int); i++) {
if (speed == name_arr[i]) {
tcflush(fd, TCIOFLUSH);
cfsetispeed(&Opt, speed_arr[i]);
cfsetospeed(&Opt, speed_arr[i]);
status = tcsetattr(fd, TCSANOW, &Opt);
if (status != 0) {
perror("tcsetattr fd1");
return;
}
tcflush(fd,TCIOFLUSH);
}
}
}
/**
* *@brief 璁剧疆涓插彛鏁版嵁浣嶏紝鍋滄?浣嶅拰鏁堥獙浣?
* *@param fd 绫诲瀷 int 鎵撳紑鐨勪覆鍙ｆ枃浠跺彞鏌?
* *@param databits 绫诲瀷 int 鏁版嵁浣? 鍙栧??涓?7 鎴栬??
* *@param stopbits 绫诲瀷 int 鍋滄?浣? 鍙栧?间负 1 鎴栬??
* *@param parity 绫诲瀷 int 鏁堥獙绫诲瀷鍙栧?间负N,E,O,,S
* */
int set_Parity(int fd,int databits,int stopbits,int parity)
{
struct termios options;
if ( tcgetattr( fd,&options) != 0) {
perror("SetupSerial 1");
return(FALSE);
}
options.c_cflag &= ~CSIZE;
switch (databits) /*璁剧疆鏁版嵁浣嶆暟*/
{
case 7:
options.c_cflag |= CS7;
break;
case 8:
options.c_cflag |= CS8;
break;
default:
fprintf(stderr,"Unsupported data size\n"); return (FALSE);
}
switch (parity)
{
case 'n':
case 'N':
options.c_cflag &= ~PARENB; /* Clear parity enable */
options.c_iflag &= ~INPCK; /* Enable parity checking */
break;
case 'o':
case 'O':
options.c_cflag |= (PARODD | PARENB); /* 璁剧疆涓哄?鏁堥獙*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'e':
case 'E':
options.c_cflag |= PARENB; /* Enable parity */
options.c_cflag &= ~PARODD; /* 杞?崲涓哄伓鏁堥獙*/
options.c_iflag |= INPCK; /* Disnable parity checking */
break;
case 'S':
case 's': /*as no parity*/
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;break;
default:
fprintf(stderr,"Unsupported parity\n");
return (FALSE);
}
/* 璁剧疆鍋滄?浣?/
switch (stopbits)
{
case 1:
options.c_cflag &= ~CSTOPB;
break;
case 2:
options.c_cflag |= CSTOPB;
break;
default:
fprintf(stderr,"Unsupported stop bits\n");
return (FALSE);
}
/* Set input parity option */
if (parity != 'n')
options.c_iflag |= INPCK;
tcflush(fd,TCIFLUSH);
options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); /*Input*/
options.c_oflag &= ~OPOST; /*Output*/
options.c_cc[VTIME] = 150; /* 璁剧疆瓒呮椂15 seconds*/
options.c_cc[VMIN] = 0; /* Update the options and do it NOW */
if (tcsetattr(fd,TCSANOW,&options) != 0)
{
perror("SetupSerial 3");
return (FALSE);
}
return (TRUE);
}
int OpenDev(char *Dev)
{
int fd = open( Dev, O_RDWR ); //| O_NOCTTY | O_NDELAY
if (-1 == fd)
{
perror("Can't Open Serial Port");
return -1;
}
else
return fd;
}
int main(int argc, char **argv){
int fd;
int nread, nwrite;
unsigned char buff[512];
char *dev = "/dev/ttyS0"; //涓插彛1
fd = OpenDev(dev);
if ( fd == -1 ){
perror("OpenDev");
exit(0);
} else {
printf("DevOpened\n");
}
set_speed(fd,1200);
if (set_Parity(fd,8,1,'N') == FALSE) {
printf("Set Parity Error\n");
exit (0);
} else {
printf("Parity set successfully\n");
}
buff[0] = 0x01;
while (1)
{
//nread = read(fd, buff, sizeof(buf));
nwrite = write(fd, buff, 1);
if ( buff[0] == 0x00 )
buff[0] = 0x01;
else
buff[0] = buff[0] << 1;
if ( nwrite < 0 ){
perror("write");
} else {
printf("%d bytes written\n", nwrite);
}
sleep(1);
}
close(fd);
exit (0);
}

复制代码

51板程序

/*******************************************
* serial communication
* send and receive
*
* written by Manio
* 04/27/08
*
* PC settings:
* baud: 1200
* parit: N
* databits: 8
* stopbit: 1
*
* BUG:
* send or receive process may be interrupted
* by receive or send interput ,and confuse
* data appear
*******************************************/
#include
void send_char_com(unsigned char ch) ;
void delay( void );
int main( void )
{
SP = 0x50;
TMOD = 0x20;
SCON = 0x50;
TH1 = 0xE6;
TL1 = 0xE6;
EA = 1;
ES = 1;
TR1 = 1;
while (1){
send_char_com( 0x83 );
delay();
}
return 0;
}
void delay( void )
{
int i;
for ( i = 0; i < 10000; ++i );
}
void serial_rev( void ) interrupt 4
{
P1 = SBUF;
RI = 0;
}
//向串口发送一个字符
void send_char_com(unsigned char ch)
{
SBUF=ch;
//TI will be set and a interrupt will be requested after one frame is sent
//TI must be clear after sending
while(TI==0);
TI=0;
}

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mondayfriday

是哦～～呵呵不好意思让大家见笑了：P
对了顺便再问一下Linux下面串口能支持的最大速率是多少？我把波特率设置为B460800后传输速度没有提高呀？

86814429

lz,我也需要一个串口发送的代码。。
如果你测试成功了，可以给我一份么。。谢了
邮箱：monkey.sh@hotmail.com

jhpotter

学习了！mark……
unix下编的？注释都是乱码……

intersong

一直用Linux，Linux环境编程比较舒服。

Linux下串口设置问题 急！！ [复制链接]

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Linux下串口设置问题急！！ [复制链接]