I read followed links and other sources, but didn't find answer for my question.
Binary data over serial terminal
Data gets corrupted during transmission over the serial port
I communicate with my embedded device through a serial port. By default, embedded Linux uses this port as a terminal. But I want to transfer also binary data (service packets) through the port. My /etc/inittab file has a "getty" call: console::respawn:/sbin/getty 115200 ttyS0
I also have /etc/passwd file with string where "admin" user launch my "cli" application after log in: admin:8Mt/Jtxcyg8AY:1000:0:admin:/tmp:/tmp/cli
My default ttyS0 settings before running the program is:
~ # stty -a
speed 115200 baud;stty: standard input
line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = ^J;
eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R;
werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 hupcl -cstopb cread -clocal -crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon ixoff
-iuclc -ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon -iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt
-echoctl echoke
~ #
So, in my cli program I do the following:
main ()
{
...
system("stty erase ^H);
system("stty -F /dev/ttyS0 -icrnl -ixon -ixoff -opost -isig -icanon -echo"); // enter in non-canonical (raw) mode
// What function do I need to use here to retrieve binary data (also symbols that > 0x7F) from /dev/ttyS0?
system("stty -F /dev/ttyS0 icrnl ixon ixoff opost isig icanon echo"); // go back to canonical mode
...
exit(0);
}
I have attempted read() function (with unsigned char buffer) to get binary data, but failed to receive correct data. I also preliminarily open /dev/ttyS0 again to get file_descriptor & use read() func.
My program sends 3 bytes: 0xAA, 0x02, 0xFE. But in syslog I always see that device receives incorrect symbols: 0x98, 0xE6, 0x18.
What is the matter? How to get correct binary data?
A whole code that I am testing at the moment.
#include "cli.h"
#include "glb_vars.h"
/******************************************
*** Definitions
******************************************/
#define APPLICATION_NAME "cli"
#define SERIALPORT_IS_CONSOLE
/******************************************
*** Constants
******************************************/
const char dev_name[] = DEV_NAME;
const char lineminstr[] = "\t--------------------------------------------------------\n";
/******************************************
*** Internal Function Declarations
******************************************/
CLI_RETVAL cliInit(void);
CLI_RETVAL cliClose(void);
void cliWorkLoop(Term_callback_t **term);
/******************************************
*** External Function Declarations
******************************************/
extern void Vectors_init(Term_callback_t **vec);
extern char** Menu_completion(const char * text, int start, int end);
/****************************************************************************/
int file_descr, max_fd;
struct termios tty, orig_tty;
fd_set work_set;
/****************************************************************************/
/*!
* \brief Init cli
*
* \return success or failure
* \retval CLI_SUCCESS, CLI_FAILURE
*
* \ingroup CLI
*/
/****************************************************************************/
CLI_RETVAL cliInit(void)
{
long spd;
signal(SIGINT, SIG_IGN);
signal(SIGHUP, SIG_IGN);
signal(SIGTERM, SIG_IGN);
signal(SIGABRT, SIG_IGN);
signal(SIGQUIT, SIG_IGN);
signal(SIGILL, SIG_IGN);
// system("stty -F /dev/ttyS0 -icrnl -ixon -ixoff -opost -isig -icanon -echo"); // enter in non-canonical mode
// system("stty -a");
// sleep(1);
#ifdef SERIALPORT_IS_CONSOLE
file_descr = STDIN_FILENO;
SYS_LOG_DEBUG("SERIALPORT IS CONSOLE");
#else
SYS_LOG_DEBUG("SERIALPORT IS NOT CONSOLE");
file_descr = open("/dev/ttyS0", O_RDWR | O_ASYNC | O_NDELAY);
if (file_descr == -1) {
// Could not open the port
perror("unable to open /dev/ttyS0");
exit(1);
}
#endif
if(tcgetattr(file_descr, &tty) < 0)
{
perror("unable to get tty attributes");
exit(1);
}
// backup tty, make it raw and apply changes
orig_tty = tty;
spd = B115200;
cfsetospeed(&tty, (speed_t)spd);
cfsetispeed(&tty, (speed_t)spd);
cfmakeraw(&tty);
tty.c_cc[VMIN] = 1;
tty.c_cc[VTIME] = 10;
tty.c_cflag &= ~CSTOPB;
tty.c_cflag &= ~CRTSCTS; /* no HW flow control? */
tty.c_cflag |= CLOCAL | CREAD;
tcsetattr(file_descr, TCSANOW, &tty);
// // update local mode flags
// tty.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
//// // renew control mode flags
//// tty.c_cflag &= ~(CBAUD | CSIZE | CSTOPB | PARENB | PARODD);
//// tty.c_cflag |= (BAUD | DATABITS | STOPBITS | PARITYON | PARITY);
// // select 'raw' output mode
// tty.c_oflag &= ~OPOST;
// // disable mapping for input mode
// tty.c_iflag &= ~(INLCR | ICRNL);
//
//
// if(tcsetattr(file_descr, TCSAFLUSH, &tty) < 0)
// {
// perror("unable to set tty attributes");
// exit(1);
// }
//
// Setup fd_set
FD_ZERO(&work_set);
FD_SET(file_descr, &work_set);
max_fd = file_descr + 1;
/* Readline lib init */
// Define application name for readline library
rl_readline_name = APPLICATION_NAME;
// Update Pointer to alternative function to create matches.
rl_attempted_completion_function = Menu_completion;
// Start readline with reading /etc/inputrc file
using_history();
stifle_history(CLI_MAX_HISTORY_SIZE);
// Some other initialization code
// ...
// ...
return CLI_SUCCESS;
}
/****************************************************************************/
/*!
* \brief Close cli
*
* \return success or failure
* \retval CLI_SUCCESS, CLI_FAILURE
*
* \ingroup CLI
*/
/****************************************************************************/
CLI_RETVAL cliClose(void)
{
// system("stty -F /dev/ttyS0 icrnl ixon ixoff opost isig icanon echo"); // enter in canonical mode
tcsetattr(file_descr, TCSANOW, &orig_tty);
// if(tcsetattr(file_descr, TCSAFLUSH, &orig_tty) < 0)
// {
// perror("unable to set orig_tty attributes");
// exit(1);
// }
close(file_descr);
return CLI_SUCCESS;
}
/****************************************************************************/
/*!
* \brief Main cli processing loop
*
* \no return
*
* \ingroup CLI
*/
/****************************************************************************/
void cliWorkLoop(Term_callback_t **term)
{
Term_callback_t *cur_term;
int8 *commandString;
uint8 ret = CLI_REFRESH, no_prompt;
char prompt_str[20];
while (1) {
cur_term = *term;
global_cmd_compl_pointer = cur_term->cmd_list;
commandString = NULL;
sprintf(prompt_str, "%s:~> ", dev_name);
if(ret == CLI_REFRESH) {
CLEAR_SCR();
if(cur_term->out != NULL) {
cur_term->out(term, commandString, &ret);
no_prompt = ret;
}
CURSOR_DOWN();
}
int n;
struct timeval timeout;
uint8 tmpBuf[32];
while (1)
{
// Setup Timeout
timeout.tv_sec = 60;
timeout.tv_usec = 0;
// Wait for new connections
n = select(max_fd, &work_set, NULL, NULL, &timeout);
if (n < 0)
{
perror("select #2 failed");
break;
}
if (n > 0)
{
/* У нас есть ввод */
if (FD_ISSET(file_descr, &work_set))
{
if (read(file_descr, tmpBuf, 10) < 0) {
perror("cannot read");
exit(1);
}
else
{
SYS_LOG_DEBUG("READ first 4 chars: 0x%X,0x%X,0x%X,0x%X", tmpBuf[0], tmpBuf[1], tmpBuf[2], tmpBuf[3]);
}
}
break;
}
}
//
//
// n = read(file_descr, tmpBuf, 5);
// if (n > 0) {
// unsigned char *p = tmpBuf;
//
// while (n-- > 0)
// printf(" 0x%x", *p++);
// printf("\r\n");
// } else {
// printf("failed to read: %d\r\n", n);
// }
//
//
exit(0);
}
CLEAR_SCR();
return;
}
/****************************************************************************/
/*!
* \brief Main cli function
*
* \param[in] argc - argument number.
* \param[in,out] argv - argument values entered by user.
*
* \return success or failure
* \retval EXIT_SUCCESS, EXIT_FAILURE
*
*
* \ingroup CLI
*/
/****************************************************************************/
int main(int argc, char *argv[])
{
Term_callback_t *term;
char logname[16];
FILE *fp;
/* Set mask for file operation */
umask(0);
system("stty erase ^H");
openlog("cli", LOG_CONS, LOG_USER);
/* Write cli start log */
syslog(LOG_NOTICE, "Console startup. Software version: %s", VERSION);
/* Find login name */
strcpy(logname, "noname");
if ((fp = popen( "whoami", "r" )) == NULL)
{
SYS_LOG_ERR("Can't open process for \"whoami\" command.");
} else
{
fgets(logname, 16, fp);
pclose(fp);
}
SYS_LOG_INFO("Console is entered by \"%s\".", logname); //getenv("USER")
/* Console initialization */
if (cliInit() != CLI_SUCCESS) {
SYS_LOG_CRIT("CLI init failed");
return EXIT_FAILURE;
}
Vectors_init(&term);
/* Console work loop */
cliWorkLoop(&term);
cliClose();
/* Exiting from cli */
SYS_LOG_INFO("\"%s\" exited from console.", logname);
return EXIT_SUCCESS;
}
