串行端口环回/双工测试,Bash还是C?(过程替代)
我将一个串行设备设置为环回(这意味着它将简单地回显它接收到的任何字符),我想测量有效的吞吐量速度。为此,我希望我能利用时间,就像在串行端口环回/双工测试,Bash还是C?(过程替代),c,linux,bash,serial-port,loopback,C,Linux,Bash,Serial Port,Loopback,我将一个串行设备设置为环回(这意味着它将简单地回显它接收到的任何字符),我想测量有效的吞吐量速度。为此,我希望我能利用时间,就像在 time bash -c '...' 其中“…”是我可以运行的命令 现在,第一个问题是,我想以2000000 bps的速度使用该设备,因此我无法使用or(它们似乎都只能达到115200 bps)。但是,将/dev/ttyUSB0作为文件使用(使用文件重定向和cat)似乎可以正常工作: # initialize serial port stty 2000000 -i
time bash -c '...'
其中“…
”是我可以运行的命令
现在,第一个问题是,我想以2000000 bps的速度使用该设备,因此我无法使用or(它们似乎都只能达到115200 bps)。但是,将/dev/ttyUSB0
作为文件使用(使用文件重定向和cat
)似乎可以正常工作:
# initialize serial port
stty 2000000 -ixon icanon </dev/ttyUSB0
# check settings
stty -a -F /dev/ttyUSB0
# in one terminal - read from serial port
while (true) do cat -A /dev/ttyUSB0 ; done
# in other terminal - write to serial port
echo "1234567890" > /dev/ttyUSB0
# back to first terminal, I now have:
# $ while (true) do cat -A /dev/ttyUSB0 ; done
# 1234567890$
# ...
在那里,除了(某种程度上)将两个进程合并成一个命令(我想,我也可以使用echo
)之外,我没有使用comm
进行任何其他用途
不幸的是,该技巧似乎不适用于串行端口,因为当我尝试它时,有时会得到:
$ comm <(echo "1234567890" > /dev/ttyUSB0) <(while (true) do cat -A /dev/ttyUSB0 ; done)
cat: /dev/ttyUSB0: Invalid argument
$comm/dev/ttyUSB0)好吧,这里有一个类似于部分答案的问题——尽管关于bash使用的问题仍然悬而未决。我试着在一些C代码解决方案中寻找一些东西——这似乎也不是小事!:)
首先,让我们看看在这种情况下,有什么可能不起作用-下面是一个来自“”的示例:
。。。换句话说,输入数据没有回声。但是,如果串行端口设置正确,我们可以获得如下会话:
$ ./sertest /dev/ttyUSB0
enter input data:
t1
enter input data:
t2
bytes: 127, line=t1
enter input data:
t3
bytes: 127, line=t2
enter input data:
t4
bytes: 127, line=t3
enter input data:
^C
。。。(但即使如此,该sertest
代码在输入大于3个字符的单词时失败。)
最后,通过一些在线挖掘,我找到了“”,它提供了一个writeread.cpp
示例。然而,对于这种逐字节“双工”的情况,这还不够——即,“注意:规范输入处理……是终端的正常处理模式……这意味着读取将只返回一整行输入。一行默认由NL(ASCII LF)终止……”;因此,我们必须通过ICANON
(换句话说,仅仅通过open
设置O非块
是不够的),在我们的代码中将串行端口设置为“非规范”(或“原始”)模式。完成后,调用writeread
也将“正确”设置serport
示例(如上)的串行端口
因此,我将一些writeread
代码更改回C,添加了所需的初始化内容,以及时间测量、发送字符串或文件的可能性,以及额外的输出流(用于将读取的串行数据“管道化”到单独的文件)。下面的代码是writeread.c
和serial.h
,使用它,我可以在下面的Bash会话中执行类似操作:
$ ./writeread /dev/ttyUSB0 2000000 writeread.c 3>myout.txt
stdalt opened; Alternative file descriptor: 3
Opening port /dev/ttyUSB0;
Got speed 2000000 (4107/0x100b);
Got file/string 'writeread.c'; opened as file (4182).
+++DONE+++
Wrote: 4182 bytes; Read: 4182 bytes; Total: 8364 bytes.
Start: 1284422340 s 443302 us; End: 1284422347 s 786999 us; Delta: 7 s 343697 us.
2000000 baud for 8N1 is 200000 Bps (bytes/sec).
Measured: write 569.47 Bps, read 569.47 Bps, total 1138.94 Bps.
$ diff writeread.c myout.txt
$ ./writeread /dev/ttyUSB0 2000000 writeread.c 3>/dev/null
stdalt opened; Alternative file descriptor: 3
Opening port /dev/ttyUSB0;
Got speed 2000000 (4107/0x100b);
Got file/string 'writeread.c'; opened as file (4182).
+++DONE+++
Wrote: 4182 bytes; Read: 4182 bytes; Total: 8364 bytes.
Start: 1284422380 s -461710 us; End: 1284422388 s 342977 us; Delta: 8 s 804687 us.
2000000 baud for 8N1 is 200000 Bps (bytes/sec).
Measured: write 474.97 Bps, read 474.97 Bps, total 949.95 Bps.
嗯:
- 第一个惊喜-如果我正在写入一个文件,它会比管道传输到
/dev/null
更快李>
- 而且,速度大约为1000 Bps,而该设备显然设定为200000 Bps李>
此时,我认为速度变慢是因为在writeread.c
中的每个写入字节之后,我们等待读取中断清除标志,然后再继续读取串行缓冲区。可能的话,如果读和写是分开的线程,那么读和写都可以尝试在单个读
或写
调用中使用更大的字节块,因此带宽会得到更好的利用?!(或者,从某种意义上说,中断处理程序的行为就像一个并行运行的“线程”——因此,通过将所有与读取相关的函数移动到中断处理程序,可能可以实现类似的功能?!)
啊,好吧,在这一点上,我非常愿意接受关于现有代码的建议/链接,比如writeread.c
,但是多线程:),当然,对于任何其他可能的Linux工具,或者可能的Bash方法(尽管Bash似乎无法实现这种控制…)
干杯
writeread.c:
/*
writeread.c - based on writeread.cpp
[SOLVED] Serial Programming, Write-Read Issue - http://www.linuxquestions.org/questions/programming-9/serial-programming-write-read-issue-822980/
build with: gcc -o writeread -Wall -g writeread.c
*/
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/time.h>
#include "serial.h"
int serport_fd;
void usage(char **argv)
{
fprintf(stdout, "Usage:\n");
fprintf(stdout, "%s port baudrate file/string\n", argv[0]);
fprintf(stdout, "Examples:\n");
fprintf(stdout, "%s /dev/ttyUSB0 115200 /path/to/somefile.txt\n", argv[0]);
fprintf(stdout, "%s /dev/ttyUSB0 115200 \"some text test\"\n", argv[0]);
}
int main( int argc, char **argv )
{
if( argc != 4 ) {
usage(argv);
return 1;
}
char *serport;
char *serspeed;
speed_t serspeed_t;
char *serfstr;
int serf_fd; // if < 0, then serfstr is a string
int bytesToSend;
int sentBytes;
char byteToSend[2];
int readChars;
int recdBytes, totlBytes;
char sResp[11];
struct timeval timeStart, timeEnd, timeDelta;
float deltasec;
/* Re: connecting alternative output stream to terminal -
* http://coding.derkeiler.com/Archive/C_CPP/comp.lang.c/2009-01/msg01616.html
* send read output to file descriptor 3 if open,
* else just send to stdout
*/
FILE *stdalt;
if(dup2(3, 3) == -1) {
fprintf(stdout, "stdalt not opened; ");
stdalt = fopen("/dev/tty", "w");
} else {
fprintf(stdout, "stdalt opened; ");
stdalt = fdopen(3, "w");
}
fprintf(stdout, "Alternative file descriptor: %d\n", fileno(stdalt));
// Get the PORT name
serport = argv[1];
fprintf(stdout, "Opening port %s;\n", serport);
// Get the baudrate
serspeed = argv[2];
serspeed_t = string_to_baud(serspeed);
fprintf(stdout, "Got speed %s (%d/0x%x);\n", serspeed, serspeed_t, serspeed_t);
//Get file or command;
serfstr = argv[3];
serf_fd = open( serfstr, O_RDONLY );
fprintf(stdout, "Got file/string '%s'; ", serfstr);
if (serf_fd < 0) {
bytesToSend = strlen(serfstr);
fprintf(stdout, "interpreting as string (%d).\n", bytesToSend);
} else {
struct stat st;
stat(serfstr, &st);
bytesToSend = st.st_size;
fprintf(stdout, "opened as file (%d).\n", bytesToSend);
}
// Open and Initialise port
serport_fd = open( serport, O_RDWR | O_NOCTTY | O_NONBLOCK );
if ( serport_fd < 0 ) { perror(serport); return 1; }
initport( serport_fd, serspeed_t );
sentBytes = 0; recdBytes = 0;
byteToSend[0]='x'; byteToSend[1]='\0';
gettimeofday( &timeStart, NULL );
// write / read loop - interleaved (i.e. will always write
// one byte at a time, before 'emptying' the read buffer )
while ( sentBytes < bytesToSend )
{
// read next byte from input...
if (serf_fd < 0) { //interpreting as string
byteToSend[0] = serfstr[sentBytes];
} else { //opened as file
read( serf_fd, &byteToSend[0], 1 );
}
if ( !writeport( serport_fd, byteToSend ) ) {
fprintf(stdout, "write failed\n");
}
//~ fprintf(stdout, "written:%s\n", byteToSend );
while ( wait_flag == TRUE );
if ( (readChars = readport( serport_fd, sResp, 10)) >= 0 )
{
//~ fprintf(stdout, "InVAL: (%d) %s\n", readChars, sResp);
recdBytes += readChars;
fprintf(stdalt, "%s", sResp);
}
wait_flag = TRUE; // was ==
//~ usleep(50000);
sentBytes++;
}
gettimeofday( &timeEnd, NULL );
// Close the open port
close( serport_fd );
if (!(serf_fd < 0)) close( serf_fd );
fprintf(stdout, "\n+++DONE+++\n");
totlBytes = sentBytes + recdBytes;
timeval_subtract(&timeDelta, &timeEnd, &timeStart);
deltasec = timeDelta.tv_sec+timeDelta.tv_usec*1e-6;
fprintf(stdout, "Wrote: %d bytes; Read: %d bytes; Total: %d bytes. \n", sentBytes, recdBytes, totlBytes);
fprintf(stdout, "Start: %ld s %ld us; End: %ld s %ld us; Delta: %ld s %ld us. \n", timeStart.tv_sec, timeStart.tv_usec, timeEnd.tv_sec, timeEnd.tv_usec, timeDelta.tv_sec, timeDelta.tv_usec);
fprintf(stdout, "%s baud for 8N1 is %d Bps (bytes/sec).\n", serspeed, atoi(serspeed)/10);
fprintf(stdout, "Measured: write %.02f Bps, read %.02f Bps, total %.02f Bps.\n", sentBytes/deltasec, recdBytes/deltasec, totlBytes/deltasec);
return 0;
}
/* serial.h
(C) 2004-5 Captain http://www.captain.at
Helper functions for "ser"
Used for testing the PIC-MMC test-board
http://www.captain.at/electronic-index.php
*/
#include <stdio.h> /* Standard input/output definitions */
#include <string.h> /* String function definitions */
#include <unistd.h> /* UNIX standard function definitions */
#include <fcntl.h> /* File control definitions */
#include <errno.h> /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#include <sys/signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#define TRUE 1
#define FALSE 0
int wait_flag = TRUE; // TRUE while no signal received
// Definition of Signal Handler
void DAQ_signal_handler_IO ( int status )
{
//~ fprintf(stdout, "received SIGIO signal %d.\n", status);
wait_flag = FALSE;
}
int writeport( int fd, char *comm )
{
int len = strlen( comm );
int n = write( fd, comm, len );
if ( n < 0 )
{
fprintf(stdout, "write failed!\n");
return 0;
}
return n;
}
int readport( int fd, char *resp, size_t nbyte )
{
int iIn = read( fd, resp, nbyte );
if ( iIn < 0 )
{
if ( errno == EAGAIN )
{
fprintf(stdout, "SERIAL EAGAIN ERROR\n");
return 0;
}
else
{
fprintf(stdout, "SERIAL read error: %d = %s\n", errno , strerror(errno));
return 0;
}
}
if ( resp[iIn-1] == '\r' )
resp[iIn-1] = '\0';
else
resp[iIn] = '\0';
return iIn;
}
int getbaud( int fd )
{
struct termios termAttr;
int inputSpeed = -1;
speed_t baudRate;
tcgetattr( fd, &termAttr );
// Get the input speed
baudRate = cfgetispeed( &termAttr );
switch ( baudRate )
{
case B0: inputSpeed = 0; break;
case B50: inputSpeed = 50; break;
case B110: inputSpeed = 110; break;
case B134: inputSpeed = 134; break;
case B150: inputSpeed = 150; break;
case B200: inputSpeed = 200; break;
case B300: inputSpeed = 300; break;
case B600: inputSpeed = 600; break;
case B1200: inputSpeed = 1200; break;
case B1800: inputSpeed = 1800; break;
case B2400: inputSpeed = 2400; break;
case B4800: inputSpeed = 4800; break;
case B9600: inputSpeed = 9600; break;
case B19200: inputSpeed = 19200; break;
case B38400: inputSpeed = 38400; break;
case B115200: inputSpeed = 115200; break;
case B2000000: inputSpeed = 2000000; break; //added
}
return inputSpeed;
}
/* ser.c
(C) 2004-5 Captain http://www.captain.at
Sends 3 characters (ABC) via the serial port (/dev/ttyS0) and reads
them back if they are returned from the PIC.
Used for testing the PIC-MMC test-board
http://www.captain.at/electronic-index.php
*/
int initport( int fd, speed_t baudRate )
{
struct termios options;
struct sigaction saio; // Definition of Signal action
// Install the signal handler before making the device asynchronous
saio.sa_handler = DAQ_signal_handler_IO;
saio.sa_flags = 0;
saio.sa_restorer = NULL;
sigaction( SIGIO, &saio, NULL );
// Allow the process to receive SIGIO
fcntl( fd, F_SETOWN, getpid() );
// Make the file descriptor asynchronous (the manual page says only
// O_APPEND and O_NONBLOCK, will work with F_SETFL...)
fcntl( fd, F_SETFL, FASYNC );
//~ fcntl( fd, F_SETFL, FNDELAY); //doesn't work; //fcntl(file, F_SETFL, 0);
// Get the current options for the port...
tcgetattr( fd, &options );
/*
// Set port settings for canonical input processing
options.c_cflag = BAUDRATE | CRTSCTS | CLOCAL | CREAD;
options.c_iflag = IGNPAR | ICRNL;
//options.c_iflag = IGNPAR;
options.c_oflag = 0;
options.c_lflag = ICANON;
//options.c_lflag = 0;
options.c_cc[VMIN] = 0;
options.c_cc[VTIME] = 0;
*/
/* ADDED - else 'read' will not return, unless it sees LF '\n' !!!!
* From: Unix Programming Frequently Asked Questions - 3. Terminal I/O -
* http://www.steve.org.uk/Reference/Unix/faq_4.html
*/
/* Disable canonical mode, and set buffer size to 1 byte */
options.c_lflag &= (~ICANON);
options.c_cc[VTIME] = 0;
options.c_cc[VMIN] = 1;
// Set the baud rates to...
cfsetispeed( &options, baudRate );
cfsetospeed( &options, baudRate );
// Enable the receiver and set local mode...
options.c_cflag |= ( CLOCAL | CREAD );
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
// Flush the input & output...
tcflush( fd, TCIOFLUSH );
// Set the new options for the port...
tcsetattr( fd, TCSANOW, &options );
return 1;
}
/*
ripped from
http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/stty.c
*/
#define STREQ(a, b) (strcmp((a), (b)) == 0)
struct speed_map
{
const char *string; /* ASCII representation. */
speed_t speed; /* Internal form. */
unsigned long int value; /* Numeric value. */
};
static struct speed_map const speeds[] =
{
{"0", B0, 0},
{"50", B50, 50},
{"75", B75, 75},
{"110", B110, 110},
{"134", B134, 134},
{"134.5", B134, 134},
{"150", B150, 150},
{"200", B200, 200},
{"300", B300, 300},
{"600", B600, 600},
{"1200", B1200, 1200},
{"1800", B1800, 1800},
{"2400", B2400, 2400},
{"4800", B4800, 4800},
{"9600", B9600, 9600},
{"19200", B19200, 19200},
{"38400", B38400, 38400},
{"exta", B19200, 19200},
{"extb", B38400, 38400},
#ifdef B57600
{"57600", B57600, 57600},
#endif
#ifdef B115200
{"115200", B115200, 115200},
#endif
#ifdef B230400
{"230400", B230400, 230400},
#endif
#ifdef B460800
{"460800", B460800, 460800},
#endif
#ifdef B500000
{"500000", B500000, 500000},
#endif
#ifdef B576000
{"576000", B576000, 576000},
#endif
#ifdef B921600
{"921600", B921600, 921600},
#endif
#ifdef B1000000
{"1000000", B1000000, 1000000},
#endif
#ifdef B1152000
{"1152000", B1152000, 1152000},
#endif
#ifdef B1500000
{"1500000", B1500000, 1500000},
#endif
#ifdef B2000000
{"2000000", B2000000, 2000000},
#endif
#ifdef B2500000
{"2500000", B2500000, 2500000},
#endif
#ifdef B3000000
{"3000000", B3000000, 3000000},
#endif
#ifdef B3500000
{"3500000", B3500000, 3500000},
#endif
#ifdef B4000000
{"4000000", B4000000, 4000000},
#endif
{NULL, 0, 0}
};
static speed_t
string_to_baud (const char *arg)
{
int i;
for (i = 0; speeds[i].string != NULL; ++i)
if (STREQ (arg, speeds[i].string))
return speeds[i].speed;
return (speed_t) -1;
}
/* http://www.gnu.org/software/libtool/manual/libc/Elapsed-Time.html
Subtract the `struct timeval' values X and Y,
storing the result in RESULT.
Return 1 if the difference is negative, otherwise 0. */
int timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y)
{
/* Perform the carry for the later subtraction by updating y. */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
y->tv_usec -= 1000000 * nsec;
y->tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
y->tv_usec += 1000000 * nsec;
y->tv_sec -= nsec;
}
/* Compute the time remaining to wait.
tv_usec is certainly positive. */
result->tv_sec = x->tv_sec - y->tv_sec;
result->tv_usec = x->tv_usec - y->tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < y->tv_sec;
}
/*
writeread.c-基于writeread.cpp
[已解决]串行编程、写-读问题-http://www.linuxquestions.org/questions/programming-9/serial-programming-write-read-issue-822980/
使用gcc-o writeread-Wall-g writeread.c构建
*/
#包括
#包括
#包括
#包括
#包括
#包括“serial.h”
国际服务中心;
无效用法(字符**argv)
{
fprintf(标准输出,“用法:\n”);
fprintf(标准输出,“%s端口波特率文件/字符串\n”,argv[0]);
fprintf(标准输出,“示例:\n”);
fprintf(stdout,“%s/dev/ttyUSB0 115200/path/to/somefile.txt\n”,argv[0]);
fprintf(stdout,“%s/dev/ttyUSB0 115200\”一些文本测试\“\n”,argv[0]);
}
int main(int argc,字符**argv)
{
如果(argc!=4){
用法(argv);
返回1;
}
字符*端口;
字符*serspeed;
速度服务速度;
char*serfstr;
int serf_fd;//如果<0,则serfstr是字符串
int bytesToSend;
整数字节;
char byteToSend[2];
int-readChars;
整数记录字节,总字节;
char-sResp[11];
结构timeval timeStart、timeEnd、timeDelta;
浮动三角洲;
/*Re:将备用输出流连接到终端-
* http://coding.derkeiler.com/Archive/C_CPP/comp.lang.c/2009-01/msg01616.html
*如果打开,将读取输出发送到文件描述符3,
*否则就发送到stdout
*/
文件*stdalt;
if(dup2(3,3)=-1){
fprintf(标准输出,“标准输出未打开;”;
stdalt=fopen(“/dev/tty”,“w”);
}否则{
fprintf(标准符号,“标准符号已打开;”);
stdalt=fdopen(3,“w”);
}
fprintf(stdout,“备用文件描述符:%d\n”,文件号(stdalt));
//获取端口名
serport=argv[1];
fprintf(stdout,“打开端口%s;\n”,serport);
//获取波特率
serspeed=argv[2];
serspeed_t=字符串至波特(serspeed);
fprintf(stdout,“获得速度%s(%d/0x%x);\n”,serspeed,serspeed,serspeed;
//获取文件或命令;
s
$ ./writeread /dev/ttyUSB0 2000000 writeread.c 3>myout.txt
stdalt opened; Alternative file descriptor: 3
Opening port /dev/ttyUSB0;
Got speed 2000000 (4107/0x100b);
Got file/string 'writeread.c'; opened as file (4182).
+++DONE+++
Wrote: 4182 bytes; Read: 4182 bytes; Total: 8364 bytes.
Start: 1284422340 s 443302 us; End: 1284422347 s 786999 us; Delta: 7 s 343697 us.
2000000 baud for 8N1 is 200000 Bps (bytes/sec).
Measured: write 569.47 Bps, read 569.47 Bps, total 1138.94 Bps.
$ diff writeread.c myout.txt
$ ./writeread /dev/ttyUSB0 2000000 writeread.c 3>/dev/null
stdalt opened; Alternative file descriptor: 3
Opening port /dev/ttyUSB0;
Got speed 2000000 (4107/0x100b);
Got file/string 'writeread.c'; opened as file (4182).
+++DONE+++
Wrote: 4182 bytes; Read: 4182 bytes; Total: 8364 bytes.
Start: 1284422380 s -461710 us; End: 1284422388 s 342977 us; Delta: 8 s 804687 us.
2000000 baud for 8N1 is 200000 Bps (bytes/sec).
Measured: write 474.97 Bps, read 474.97 Bps, total 949.95 Bps.
/*
writeread.c - based on writeread.cpp
[SOLVED] Serial Programming, Write-Read Issue - http://www.linuxquestions.org/questions/programming-9/serial-programming-write-read-issue-822980/
build with: gcc -o writeread -Wall -g writeread.c
*/
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/time.h>
#include "serial.h"
int serport_fd;
void usage(char **argv)
{
fprintf(stdout, "Usage:\n");
fprintf(stdout, "%s port baudrate file/string\n", argv[0]);
fprintf(stdout, "Examples:\n");
fprintf(stdout, "%s /dev/ttyUSB0 115200 /path/to/somefile.txt\n", argv[0]);
fprintf(stdout, "%s /dev/ttyUSB0 115200 \"some text test\"\n", argv[0]);
}
int main( int argc, char **argv )
{
if( argc != 4 ) {
usage(argv);
return 1;
}
char *serport;
char *serspeed;
speed_t serspeed_t;
char *serfstr;
int serf_fd; // if < 0, then serfstr is a string
int bytesToSend;
int sentBytes;
char byteToSend[2];
int readChars;
int recdBytes, totlBytes;
char sResp[11];
struct timeval timeStart, timeEnd, timeDelta;
float deltasec;
/* Re: connecting alternative output stream to terminal -
* http://coding.derkeiler.com/Archive/C_CPP/comp.lang.c/2009-01/msg01616.html
* send read output to file descriptor 3 if open,
* else just send to stdout
*/
FILE *stdalt;
if(dup2(3, 3) == -1) {
fprintf(stdout, "stdalt not opened; ");
stdalt = fopen("/dev/tty", "w");
} else {
fprintf(stdout, "stdalt opened; ");
stdalt = fdopen(3, "w");
}
fprintf(stdout, "Alternative file descriptor: %d\n", fileno(stdalt));
// Get the PORT name
serport = argv[1];
fprintf(stdout, "Opening port %s;\n", serport);
// Get the baudrate
serspeed = argv[2];
serspeed_t = string_to_baud(serspeed);
fprintf(stdout, "Got speed %s (%d/0x%x);\n", serspeed, serspeed_t, serspeed_t);
//Get file or command;
serfstr = argv[3];
serf_fd = open( serfstr, O_RDONLY );
fprintf(stdout, "Got file/string '%s'; ", serfstr);
if (serf_fd < 0) {
bytesToSend = strlen(serfstr);
fprintf(stdout, "interpreting as string (%d).\n", bytesToSend);
} else {
struct stat st;
stat(serfstr, &st);
bytesToSend = st.st_size;
fprintf(stdout, "opened as file (%d).\n", bytesToSend);
}
// Open and Initialise port
serport_fd = open( serport, O_RDWR | O_NOCTTY | O_NONBLOCK );
if ( serport_fd < 0 ) { perror(serport); return 1; }
initport( serport_fd, serspeed_t );
sentBytes = 0; recdBytes = 0;
byteToSend[0]='x'; byteToSend[1]='\0';
gettimeofday( &timeStart, NULL );
// write / read loop - interleaved (i.e. will always write
// one byte at a time, before 'emptying' the read buffer )
while ( sentBytes < bytesToSend )
{
// read next byte from input...
if (serf_fd < 0) { //interpreting as string
byteToSend[0] = serfstr[sentBytes];
} else { //opened as file
read( serf_fd, &byteToSend[0], 1 );
}
if ( !writeport( serport_fd, byteToSend ) ) {
fprintf(stdout, "write failed\n");
}
//~ fprintf(stdout, "written:%s\n", byteToSend );
while ( wait_flag == TRUE );
if ( (readChars = readport( serport_fd, sResp, 10)) >= 0 )
{
//~ fprintf(stdout, "InVAL: (%d) %s\n", readChars, sResp);
recdBytes += readChars;
fprintf(stdalt, "%s", sResp);
}
wait_flag = TRUE; // was ==
//~ usleep(50000);
sentBytes++;
}
gettimeofday( &timeEnd, NULL );
// Close the open port
close( serport_fd );
if (!(serf_fd < 0)) close( serf_fd );
fprintf(stdout, "\n+++DONE+++\n");
totlBytes = sentBytes + recdBytes;
timeval_subtract(&timeDelta, &timeEnd, &timeStart);
deltasec = timeDelta.tv_sec+timeDelta.tv_usec*1e-6;
fprintf(stdout, "Wrote: %d bytes; Read: %d bytes; Total: %d bytes. \n", sentBytes, recdBytes, totlBytes);
fprintf(stdout, "Start: %ld s %ld us; End: %ld s %ld us; Delta: %ld s %ld us. \n", timeStart.tv_sec, timeStart.tv_usec, timeEnd.tv_sec, timeEnd.tv_usec, timeDelta.tv_sec, timeDelta.tv_usec);
fprintf(stdout, "%s baud for 8N1 is %d Bps (bytes/sec).\n", serspeed, atoi(serspeed)/10);
fprintf(stdout, "Measured: write %.02f Bps, read %.02f Bps, total %.02f Bps.\n", sentBytes/deltasec, recdBytes/deltasec, totlBytes/deltasec);
return 0;
}
/* serial.h
(C) 2004-5 Captain http://www.captain.at
Helper functions for "ser"
Used for testing the PIC-MMC test-board
http://www.captain.at/electronic-index.php
*/
#include <stdio.h> /* Standard input/output definitions */
#include <string.h> /* String function definitions */
#include <unistd.h> /* UNIX standard function definitions */
#include <fcntl.h> /* File control definitions */
#include <errno.h> /* Error number definitions */
#include <termios.h> /* POSIX terminal control definitions */
#include <sys/signal.h>
#include <sys/stat.h>
#include <sys/types.h>
#define TRUE 1
#define FALSE 0
int wait_flag = TRUE; // TRUE while no signal received
// Definition of Signal Handler
void DAQ_signal_handler_IO ( int status )
{
//~ fprintf(stdout, "received SIGIO signal %d.\n", status);
wait_flag = FALSE;
}
int writeport( int fd, char *comm )
{
int len = strlen( comm );
int n = write( fd, comm, len );
if ( n < 0 )
{
fprintf(stdout, "write failed!\n");
return 0;
}
return n;
}
int readport( int fd, char *resp, size_t nbyte )
{
int iIn = read( fd, resp, nbyte );
if ( iIn < 0 )
{
if ( errno == EAGAIN )
{
fprintf(stdout, "SERIAL EAGAIN ERROR\n");
return 0;
}
else
{
fprintf(stdout, "SERIAL read error: %d = %s\n", errno , strerror(errno));
return 0;
}
}
if ( resp[iIn-1] == '\r' )
resp[iIn-1] = '\0';
else
resp[iIn] = '\0';
return iIn;
}
int getbaud( int fd )
{
struct termios termAttr;
int inputSpeed = -1;
speed_t baudRate;
tcgetattr( fd, &termAttr );
// Get the input speed
baudRate = cfgetispeed( &termAttr );
switch ( baudRate )
{
case B0: inputSpeed = 0; break;
case B50: inputSpeed = 50; break;
case B110: inputSpeed = 110; break;
case B134: inputSpeed = 134; break;
case B150: inputSpeed = 150; break;
case B200: inputSpeed = 200; break;
case B300: inputSpeed = 300; break;
case B600: inputSpeed = 600; break;
case B1200: inputSpeed = 1200; break;
case B1800: inputSpeed = 1800; break;
case B2400: inputSpeed = 2400; break;
case B4800: inputSpeed = 4800; break;
case B9600: inputSpeed = 9600; break;
case B19200: inputSpeed = 19200; break;
case B38400: inputSpeed = 38400; break;
case B115200: inputSpeed = 115200; break;
case B2000000: inputSpeed = 2000000; break; //added
}
return inputSpeed;
}
/* ser.c
(C) 2004-5 Captain http://www.captain.at
Sends 3 characters (ABC) via the serial port (/dev/ttyS0) and reads
them back if they are returned from the PIC.
Used for testing the PIC-MMC test-board
http://www.captain.at/electronic-index.php
*/
int initport( int fd, speed_t baudRate )
{
struct termios options;
struct sigaction saio; // Definition of Signal action
// Install the signal handler before making the device asynchronous
saio.sa_handler = DAQ_signal_handler_IO;
saio.sa_flags = 0;
saio.sa_restorer = NULL;
sigaction( SIGIO, &saio, NULL );
// Allow the process to receive SIGIO
fcntl( fd, F_SETOWN, getpid() );
// Make the file descriptor asynchronous (the manual page says only
// O_APPEND and O_NONBLOCK, will work with F_SETFL...)
fcntl( fd, F_SETFL, FASYNC );
//~ fcntl( fd, F_SETFL, FNDELAY); //doesn't work; //fcntl(file, F_SETFL, 0);
// Get the current options for the port...
tcgetattr( fd, &options );
/*
// Set port settings for canonical input processing
options.c_cflag = BAUDRATE | CRTSCTS | CLOCAL | CREAD;
options.c_iflag = IGNPAR | ICRNL;
//options.c_iflag = IGNPAR;
options.c_oflag = 0;
options.c_lflag = ICANON;
//options.c_lflag = 0;
options.c_cc[VMIN] = 0;
options.c_cc[VTIME] = 0;
*/
/* ADDED - else 'read' will not return, unless it sees LF '\n' !!!!
* From: Unix Programming Frequently Asked Questions - 3. Terminal I/O -
* http://www.steve.org.uk/Reference/Unix/faq_4.html
*/
/* Disable canonical mode, and set buffer size to 1 byte */
options.c_lflag &= (~ICANON);
options.c_cc[VTIME] = 0;
options.c_cc[VMIN] = 1;
// Set the baud rates to...
cfsetispeed( &options, baudRate );
cfsetospeed( &options, baudRate );
// Enable the receiver and set local mode...
options.c_cflag |= ( CLOCAL | CREAD );
options.c_cflag &= ~PARENB;
options.c_cflag &= ~CSTOPB;
options.c_cflag &= ~CSIZE;
options.c_cflag |= CS8;
// Flush the input & output...
tcflush( fd, TCIOFLUSH );
// Set the new options for the port...
tcsetattr( fd, TCSANOW, &options );
return 1;
}
/*
ripped from
http://git.savannah.gnu.org/cgit/coreutils.git/tree/src/stty.c
*/
#define STREQ(a, b) (strcmp((a), (b)) == 0)
struct speed_map
{
const char *string; /* ASCII representation. */
speed_t speed; /* Internal form. */
unsigned long int value; /* Numeric value. */
};
static struct speed_map const speeds[] =
{
{"0", B0, 0},
{"50", B50, 50},
{"75", B75, 75},
{"110", B110, 110},
{"134", B134, 134},
{"134.5", B134, 134},
{"150", B150, 150},
{"200", B200, 200},
{"300", B300, 300},
{"600", B600, 600},
{"1200", B1200, 1200},
{"1800", B1800, 1800},
{"2400", B2400, 2400},
{"4800", B4800, 4800},
{"9600", B9600, 9600},
{"19200", B19200, 19200},
{"38400", B38400, 38400},
{"exta", B19200, 19200},
{"extb", B38400, 38400},
#ifdef B57600
{"57600", B57600, 57600},
#endif
#ifdef B115200
{"115200", B115200, 115200},
#endif
#ifdef B230400
{"230400", B230400, 230400},
#endif
#ifdef B460800
{"460800", B460800, 460800},
#endif
#ifdef B500000
{"500000", B500000, 500000},
#endif
#ifdef B576000
{"576000", B576000, 576000},
#endif
#ifdef B921600
{"921600", B921600, 921600},
#endif
#ifdef B1000000
{"1000000", B1000000, 1000000},
#endif
#ifdef B1152000
{"1152000", B1152000, 1152000},
#endif
#ifdef B1500000
{"1500000", B1500000, 1500000},
#endif
#ifdef B2000000
{"2000000", B2000000, 2000000},
#endif
#ifdef B2500000
{"2500000", B2500000, 2500000},
#endif
#ifdef B3000000
{"3000000", B3000000, 3000000},
#endif
#ifdef B3500000
{"3500000", B3500000, 3500000},
#endif
#ifdef B4000000
{"4000000", B4000000, 4000000},
#endif
{NULL, 0, 0}
};
static speed_t
string_to_baud (const char *arg)
{
int i;
for (i = 0; speeds[i].string != NULL; ++i)
if (STREQ (arg, speeds[i].string))
return speeds[i].speed;
return (speed_t) -1;
}
/* http://www.gnu.org/software/libtool/manual/libc/Elapsed-Time.html
Subtract the `struct timeval' values X and Y,
storing the result in RESULT.
Return 1 if the difference is negative, otherwise 0. */
int timeval_subtract (struct timeval *result, struct timeval *x, struct timeval *y)
{
/* Perform the carry for the later subtraction by updating y. */
if (x->tv_usec < y->tv_usec) {
int nsec = (y->tv_usec - x->tv_usec) / 1000000 + 1;
y->tv_usec -= 1000000 * nsec;
y->tv_sec += nsec;
}
if (x->tv_usec - y->tv_usec > 1000000) {
int nsec = (x->tv_usec - y->tv_usec) / 1000000;
y->tv_usec += 1000000 * nsec;
y->tv_sec -= nsec;
}
/* Compute the time remaining to wait.
tv_usec is certainly positive. */
result->tv_sec = x->tv_sec - y->tv_sec;
result->tv_usec = x->tv_usec - y->tv_usec;
/* Return 1 if result is negative. */
return x->tv_sec < y->tv_sec;
}
$ ./writeread /dev/ttyUSB0 115200 writeread.c 3>myout.txt
stdalt opened; Alternative file descriptor: 3
Opening port /dev/ttyUSB0;
Got speed 115200 (4098/0x1002);
Got file/string 'writeread.c'; opened as file (6131).
write_thread_function spawned
write: 6131
read: 18
read: 64
read: 110
read: 156
read: 202
...
read: 6066
read: 6089
read: 6123
read: 6131
+++DONE+++
Wrote: 6131 bytes; Read: 6131 bytes; Total: 12262 bytes.
Start: 1284462824 s 141104 us; End: 1284462824 s 682598 us; Delta: 0 s 541494 us.
115200 baud for 8N1 is 11520 Bps (bytes/sec).
Measured: write 11322.38 Bps (98.28%), read 11322.38 Bps (98.28%), total 22644.76 Bps.
$ diff writeread.c myout.txt
$
/*
writeread.c - based on writeread.cpp
[SOLVED] Serial Programming, Write-Read Issue - http://www.linuxquestions.org/questions/programming-9/serial-programming-write-read-issue-822980/
build with: gcc -o writeread -lpthread -Wall -g writeread.c
*/
#include <stdio.h>
#include <string.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/time.h>
#include <pthread.h>
#include "serial.h"
int serport_fd;
//POSIX Threads Programming - https://computing.llnl.gov/tutorials/pthreads/#PassingArguments
struct write_thread_data{
int fd;
char* comm; //string to send
int bytesToSend;
int writtenBytes;
};
void usage(char **argv)
{
fprintf(stdout, "Usage:\n");
fprintf(stdout, "%s port baudrate file/string\n", argv[0]);
fprintf(stdout, "Examples:\n");
fprintf(stdout, "%s /dev/ttyUSB0 115200 /path/to/somefile.txt\n", argv[0]);
fprintf(stdout, "%s /dev/ttyUSB0 115200 \"some text test\"\n", argv[0]);
}
// POSIX threads explained - http://www.ibm.com/developerworks/library/l-posix1.html
// instead of writeport
void *write_thread_function(void *arg) {
int lastBytesWritten;
struct write_thread_data *my_data;
my_data = (struct write_thread_data *) arg;
fprintf(stdout, "write_thread_function spawned\n");
my_data->writtenBytes = 0;
while(my_data->writtenBytes < my_data->bytesToSend)
{
lastBytesWritten = write( my_data->fd, my_data->comm + my_data->writtenBytes, my_data->bytesToSend - my_data->writtenBytes );
my_data->writtenBytes += lastBytesWritten;
if ( lastBytesWritten < 0 )
{
fprintf(stdout, "write failed!\n");
return 0;
}
fprintf(stderr, " write: %d - %d\n", lastBytesWritten, my_data->writtenBytes);
}
return NULL; //pthread_exit(NULL)
}
int main( int argc, char **argv )
{
if( argc != 4 ) {
usage(argv);
return 1;
}
char *serport;
char *serspeed;
speed_t serspeed_t;
char *serfstr;
int serf_fd; // if < 0, then serfstr is a string
int sentBytes;
int readChars;
int recdBytes, totlBytes;
char* sResp;
char* sRespTotal;
struct timeval timeStart, timeEnd, timeDelta;
float deltasec, expectBps, measReadBps, measWriteBps;
struct write_thread_data wrdata;
pthread_t myWriteThread;
/* Re: connecting alternative output stream to terminal -
* http://coding.derkeiler.com/Archive/C_CPP/comp.lang.c/2009-01/msg01616.html
* send read output to file descriptor 3 if open,
* else just send to stdout
*/
FILE *stdalt;
if(dup2(3, 3) == -1) {
fprintf(stdout, "stdalt not opened; ");
stdalt = fopen("/dev/tty", "w");
} else {
fprintf(stdout, "stdalt opened; ");
stdalt = fdopen(3, "w");
}
fprintf(stdout, "Alternative file descriptor: %d\n", fileno(stdalt));
// Get the PORT name
serport = argv[1];
fprintf(stdout, "Opening port %s;\n", serport);
// Get the baudrate
serspeed = argv[2];
serspeed_t = string_to_baud(serspeed);
fprintf(stdout, "Got speed %s (%d/0x%x);\n", serspeed, serspeed_t, serspeed_t);
//Get file or command;
serfstr = argv[3];
serf_fd = open( serfstr, O_RDONLY );
fprintf(stdout, "Got file/string '%s'; ", serfstr);
if (serf_fd < 0) {
wrdata.bytesToSend = strlen(serfstr);
wrdata.comm = serfstr; //pointer already defined
fprintf(stdout, "interpreting as string (%d).\n", wrdata.bytesToSend);
} else {
struct stat st;
stat(serfstr, &st);
wrdata.bytesToSend = st.st_size;
wrdata.comm = (char *)calloc(wrdata.bytesToSend, sizeof(char));
read(serf_fd, wrdata.comm, wrdata.bytesToSend);
fprintf(stdout, "opened as file (%d).\n", wrdata.bytesToSend);
}
sResp = (char *)calloc(wrdata.bytesToSend, sizeof(char));
sRespTotal = (char *)calloc(wrdata.bytesToSend, sizeof(char));
// Open and Initialise port
serport_fd = open( serport, O_RDWR | O_NOCTTY | O_NONBLOCK );
if ( serport_fd < 0 ) { perror(serport); return 1; }
initport( serport_fd, serspeed_t );
wrdata.fd = serport_fd;
sentBytes = 0; recdBytes = 0;
gettimeofday( &timeStart, NULL );
// start the thread for writing..
if ( pthread_create( &myWriteThread, NULL, write_thread_function, (void *) &wrdata) ) {
printf("error creating thread.");
abort();
}
// run read loop
while ( recdBytes < wrdata.bytesToSend )
{
while ( wait_flag == TRUE );
if ( (readChars = read( serport_fd, sResp, wrdata.bytesToSend)) >= 0 )
{
//~ fprintf(stdout, "InVAL: (%d) %s\n", readChars, sResp);
// binary safe - add sResp chunk to sRespTotal
memmove(sRespTotal+recdBytes, sResp+0, readChars*sizeof(char));
/* // text safe, but not binary:
sResp[readChars] = '\0';
fprintf(stdalt, "%s", sResp);
*/
recdBytes += readChars;
} else {
if ( errno == EAGAIN )
{
fprintf(stdout, "SERIAL EAGAIN ERROR\n");
return 0;
}
else
{
fprintf(stdout, "SERIAL read error: %d = %s\n", errno , strerror(errno));
return 0;
}
}
fprintf(stderr, " read: %d\n", recdBytes);
wait_flag = TRUE; // was ==
//~ usleep(50000);
}
if ( pthread_join ( myWriteThread, NULL ) ) {
printf("error joining thread.");
abort();
}
gettimeofday( &timeEnd, NULL );
// binary safe - dump sRespTotal to stdalt
fwrite(sRespTotal, sizeof(char), recdBytes, stdalt);
// Close the open port
close( serport_fd );
if (!(serf_fd < 0)) {
close( serf_fd );
free(wrdata.comm);
}
free(sResp);
free(sRespTotal);
fprintf(stdout, "\n+++DONE+++\n");
sentBytes = wrdata.writtenBytes;
totlBytes = sentBytes + recdBytes;
timeval_subtract(&timeDelta, &timeEnd, &timeStart);
deltasec = timeDelta.tv_sec+timeDelta.tv_usec*1e-6;
expectBps = atoi(serspeed)/10.0f;
measWriteBps = sentBytes/deltasec;
measReadBps = recdBytes/deltasec;
fprintf(stdout, "Wrote: %d bytes; Read: %d bytes; Total: %d bytes. \n", sentBytes, recdBytes, totlBytes);
fprintf(stdout, "Start: %ld s %ld us; End: %ld s %ld us; Delta: %ld s %ld us. \n", timeStart.tv_sec, timeStart.tv_usec, timeEnd.tv_sec, timeEnd.tv_usec, timeDelta.tv_sec, timeDelta.tv_usec);
fprintf(stdout, "%s baud for 8N1 is %d Bps (bytes/sec).\n", serspeed, (int)expectBps);
fprintf(stdout, "Measured: write %.02f Bps (%.02f%%), read %.02f Bps (%.02f%%), total %.02f Bps.\n", measWriteBps, (measWriteBps/expectBps)*100, measReadBps, (measReadBps/expectBps)*100, totlBytes/deltasec);
return 0;
}