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linux串口写命令行 linux串口编程实例

linux下的串口编程

这有个友善的串口例程,参考下吧,用gcc编译可以在linux下用

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# include stdio.h

# include stdlib.h

# include termio.h

# include unistd.h

# include fcntl.h

# include getopt.h

# include time.h

# include errno.h

# include string.h

int CommFd, TtyFd;

static void Error(const char *Msg)

{

fprintf (stderr, "%s\n", Msg);

fprintf (stderr, "strerror() is %s\n", strerror(errno));

exit(1);

}

static void Warning(const char *Msg)

{

fprintf (stderr, "Warning: %s\n", Msg);

}

static int SerialSpeed(const char *SpeedString)

{

int SpeedNumber = atoi(SpeedString);

# define TestSpeed(Speed) if (SpeedNumber == Speed) return B##Speed

TestSpeed(1200);

TestSpeed(2400);

TestSpeed(4800);

TestSpeed(9600);

TestSpeed(19200);

TestSpeed(38400);

TestSpeed(57600);

TestSpeed(115200);

TestSpeed(230400);

Error("Bad speed");

return -1;

}

static void PrintUsage(void)

{

fprintf(stderr, "comtest - interactive program of comm port\n");

fprintf(stderr, "press [ESC] 3 times to quit\n\n");

fprintf(stderr, "Usage: comtest [-d device] [-t tty] [-s speed] [-7] [-c] [-x] [-o] [-h]\n");

fprintf(stderr, " -7 7 bit\n");

fprintf(stderr, " -x hex mode\n");

fprintf(stderr, " -o output to stdout too\n");

fprintf(stderr, " -c stdout output use color\n");

fprintf(stderr, " -h print this help\n");

exit(-1);

}

static inline void WaitFdWriteable(int Fd)

{

fd_set WriteSetFD;

FD_ZERO(WriteSetFD);

FD_SET(Fd, WriteSetFD);

if (select(Fd + 1, NULL, WriteSetFD, NULL, NULL) 0) {

Error(strerror(errno));

}

}

int sendUart(char c)

{

WaitFdWriteable(CommFd);

return write(CommFd, c, 1);

}

char recUart()

{

char c='\0';

if (FD_ISSET(CommFd, ReadSetFD))

{

if(read(CommFd, c, 1) == 1) return c;

else printf("No data to receive.\n");

}

}

int main(int argc, char **argv)

{

struct termios TtyAttr;

struct termios BackupTtyAttr;

int DeviceSpeed = B115200;

int TtySpeed = B115200;

int ByteBits = CS8;

const char *DeviceName = "/dev/ttyS0";

const char *TtyName = "/dev/tty";

int OutputHex = 0;

int OutputToStdout = 0;

int UseColor = 0;

printf("Now we start.\n");

opterr = 0;

for (;;) {

int c = getopt(argc, argv, "d:s:t:7xoch");

if (c == -1)

break;

switch(c) {

case 'd':

DeviceName = optarg;

break;

case 't':

TtyName = optarg;

break;

case 's':

if (optarg[0] == 'd') {

DeviceSpeed = SerialSpeed(optarg + 1);

} else if (optarg[0] == 't') {

TtySpeed = SerialSpeed(optarg + 1);

} else

TtySpeed = DeviceSpeed = SerialSpeed(optarg);

break;

case 'o':

OutputToStdout = 1;

break;

case '7':

ByteBits = CS7;

break;

case 'x':

OutputHex = 1;

break;

case 'c':

UseColor = 1;

break;

case '?':

case 'h':

default:

PrintUsage();

}

}

if (optind != argc)

PrintUsage();

CommFd = open(DeviceName, O_RDWR, 0);

if (CommFd 0)

Error("Unable to open device");

if (fcntl(CommFd, F_SETFL, O_NONBLOCK) 0)

Error("Unable set to NONBLOCK mode");

memset(TtyAttr, 0, sizeof(struct termios));

TtyAttr.c_iflag = IGNPAR;

TtyAttr.c_cflag = DeviceSpeed | HUPCL | ByteBits | CREAD | CLOCAL;

TtyAttr.c_cc[VMIN] = 1;

if (tcsetattr(CommFd, TCSANOW, TtyAttr) 0)

Warning("Unable to set comm port");

TtyFd = open(TtyName, O_RDWR | O_NDELAY, 0);

if (TtyFd 0)

Error("Unable to open tty");

TtyAttr.c_cflag = TtySpeed | HUPCL | ByteBits | CREAD | CLOCAL;

if (tcgetattr(TtyFd, BackupTtyAttr) 0)

Error("Unable to get tty");

if (tcsetattr(TtyFd, TCSANOW, TtyAttr) 0)

Error("Unable to set tty");

for (;;) {

unsigned char Char = 0;

fd_set ReadSetFD;

void OutputStdChar(FILE *File) {

char Buffer[10];

int Len = sprintf(Buffer, OutputHex ? "%.2X " : "%c", Char);

fwrite(Buffer, 1, Len, File);

}

FD_ZERO(ReadSetFD);

FD_SET(CommFd, ReadSetFD);

FD_SET( TtyFd, ReadSetFD);

# define max(x,y) ( ((x) = (y)) ? (x) : (y) )

if (select(max(CommFd, TtyFd) + 1, ReadSetFD, NULL, NULL, NULL) 0) {

Error(strerror(errno));

}

# undef max

if (FD_ISSET(CommFd, ReadSetFD)) {

while (read(CommFd, Char, 1) == 1) {

WaitFdWriteable(TtyFd);

if (write(TtyFd, Char, 1) 0) {

Error(strerror(errno));

}

if (OutputToStdout) {

if (UseColor)

fwrite("\x1b[01;34m", 1, 8, stdout);

OutputStdChar(stdout);

if (UseColor)

fwrite("\x1b[00m", 1, 8, stdout);

fflush(stdout);

}

}

}

if (FD_ISSET(TtyFd, ReadSetFD)) {

while (read(TtyFd, Char, 1) == 1) {

static int EscKeyCount = 0;

WaitFdWriteable(CommFd);

if (write(CommFd, Char, 1) 0) {

Error(strerror(errno));

}

if (OutputToStdout) {

if (UseColor)

fwrite("\x1b[01;31m", 1, 8, stderr);

OutputStdChar(stderr);

if (UseColor)

fwrite("\x1b[00m", 1, 8, stderr);

fflush(stderr);

}

if (Char == '\x1b') {

EscKeyCount ++;

if (EscKeyCount = 3)

goto ExitLabel;

} else

EscKeyCount = 0;

}

}

}

ExitLabel:

if (tcsetattr(TtyFd, TCSANOW, BackupTtyAttr) 0)

Error("Unable to set tty");

return 0;

}

linux shell 串口

最好能将问题更准确的描述,看的费力! 脚本和串口命令以及运行结果截个图上来看看

我估计是

参数没有正确传递进去。

串口读取从SHELL脚本传递进来的参数应该不是正确的。

你看一下运行串口程序的时候,是否开启了一个新的进程,并且重新初始化了所有变量。

Linux普通用户运行串口

将USB串口设备插入USB口后,会在/dev/目录下生成/dev/ttyUSB0文件(也可能为/dev/ttyUSB1,/dev/ttyUSB2...),

查看此文件

输出为:

c说明表明设备为字符设备文件(d表示目录文件,-表示普通文件,l表示链接文件,b表示块文件),

其中rw-rw----表示root用户作为文件所有者可以读和写,dialout用户组内的用户可以读和写,其他用户不允许读、写和执行(r表示可读,w表示可写,x表示可执行)

因此,需要将当前用户增加到dialout用户组中


标题名称:linux串口写命令行 linux串口编程实例
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