Setting UART speed to custom value for sending break.

Used with 19200 baud rate for data TX, break generated by
sending 0x00 with 12800 baud rate.

PCAN LIN converter configured as a slave does respond.

diff --git a/misc/tty_lin_master/Makefile b/misc/tty_lin_master/Makefile
index 6bf535a90f6a7fee2cafae564423002840b1997f..06443ed3dd6894018a8be73d0479857a7fc5a8fa 100644 (file)
--- a/misc/tty_lin_master/Makefile
+++ b/misc/tty_lin_master/Makefile
@@ -1,2 +1,2 @@
 all: main.c
-       gcc main.c -std=gnu99 -Wall -pedantic -o main
+       gcc main.c -lrt -std=gnu99 -Wall -pedantic -o main

diff --git a/misc/tty_lin_master/main.c b/misc/tty_lin_master/main.c
index a61566ce6432449a42febc79dffaeb075b7f7690..dfad09a3c0dcfd259e9d616795291ddac38bcea4 100644 (file)
--- a/misc/tty_lin_master/main.c
+++ b/misc/tty_lin_master/main.c
@@ -9,22 +9,30 @@
 #include <string.h>
 #include <termios.h>
 #include <stdint.h>
-
-#define UART_SPEED             B2400
+#include <sys/ioctl.h>
+#include <linux/serial.h> /* struct struct_serial */
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h> /* clock_nanosleep */
 
 #define LIN_HDR_SIZE           2
 #define LIN_PKT_MAX_SIZE       16 /* FIXME */
-struct termios term_attr;
+
+int lin_baudrate = B19200;
+int lin_break_baud = 0;
+
+struct termios tattr_orig;
+struct termios tattr;
+struct serial_struct sattr;
 /* ------------------------------------------------------------------------ */
 static void reset_input_mode(int tty)
 {
-       tcsetattr(tty, TCSANOW, &term_attr);
+       tcsetattr(tty, TCSANOW, &tattr_orig);
 }
 
 static void set_input_mode(int tty, speed_t speed)
 {
        int status;
-       struct termios tattr;
 
        /* Flush input and output queues. */
        if (tcflush(tty, TCIOFLUSH) != 0) {
@@ -39,19 +47,49 @@ static void set_input_mode(int tty, speed_t speed)
        }
 
        /* Save settings for later restoring */
-       tcgetattr(tty, &term_attr);
+       tcgetattr(tty, &tattr_orig);
+       if (ioctl(tty, TIOCGSERIAL, &sattr) < 0) {
+               perror("ioctl()");
+       }
 
        /* RAW mode */
        tcgetattr(tty, &tattr);
-       tattr.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
-                               | INLCR | IGNCR | ICRNL | IXON);
-       tattr.c_oflag &= ~OPOST;
-       tattr.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
-       tattr.c_cflag &= ~(CSIZE | PARENB);
-       tattr.c_cflag |= CS8;
-
-       tattr.c_cc[VMIN] = 1;
-       tattr.c_cc[VTIME] = 0;
+//     tattr.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
+//                             | INLCR | IGNCR | ICRNL | IXON);
+//     tattr.c_oflag &= ~OPOST;
+//     tattr.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+//     tattr.c_cflag &= ~(CSIZE | PARENB);
+//     tattr.c_cflag |= CS8;
+
+       /* Sets hardware control flags: */
+       /* 8 data bits                  */
+       /* Enable receiver              */
+       /* Ignore CD (local connection) */
+       tattr.c_cflag = CS8 | CREAD | CLOCAL;
+       tattr.c_iflag = 0;
+       tattr.c_oflag = NL0 | CR0 | TAB0 | BS0 | VT0 | FF0;
+       tattr.c_lflag = 0;
+
+//     tattr.c_cc[VMIN] = 1;
+//     tattr.c_cc[VTIME] = 0;
+
+       tattr.c_cc[VINTR]    = '\0';
+       tattr.c_cc[VQUIT]    = '\0';
+       tattr.c_cc[VERASE]   = '\0';
+       tattr.c_cc[VKILL]    = '\0';
+       tattr.c_cc[VEOF]     = '\0';
+       tattr.c_cc[VTIME]    = '\0';
+       tattr.c_cc[VMIN]     = 1;
+       tattr.c_cc[VSWTC]    = '\0';
+       tattr.c_cc[VSTART]   = '\0';
+       tattr.c_cc[VSTOP]    = '\0';
+       tattr.c_cc[VSUSP]    = '\0';
+       tattr.c_cc[VEOL]     = '\0';
+       tattr.c_cc[VREPRINT] = '\0';
+       tattr.c_cc[VDISCARD] = '\0';
+       tattr.c_cc[VWERASE]  = '\0';
+       tattr.c_cc[VLNEXT]   = '\0';
+       tattr.c_cc[VEOL2]    = '\0';
 
        /* Set TX, RX speed */
        cfsetispeed(&tattr, speed);
@@ -61,27 +99,69 @@ static void set_input_mode(int tty, speed_t speed)
        if (status == -1)
                perror("tcsetattr()");
 
+       /* Baudrate for sending LIN break */
+       //lin_break_baud = ((lin_baudrate * 2) / 3);
+       lin_break_baud = 12800;
 }
 
 
 int send_header(int tty)
 {
-       struct termios tattr;
        int buff[3];
        buff[0] = 0x00; /* Sync byte */
        buff[1] = 0x55; /* Sync byte */
        buff[2] = 0xC1; /* LIN ID: 1 */
 
+       printf("send_header() invoked\n");
+       tcflush(tty, TCIOFLUSH);
 
-       /* Decrease speed to send BREAK (simulated with 0x00 data frame)*/      
-       tcgetattr(tty, &tattr);
-       cfsetospeed(&tattr, B1200);
-       tcsetattr(tty, TCSADRAIN, &tattr);
+       /* Decrease speed to send BREAK
+        * (simulated with 0x00 data frame) */
+
+       /* Set "non-standard" baudrate in serial_struct struct */
+       sattr.flags &= (~ASYNC_SPD_MASK);
+       sattr.flags |= (ASYNC_SPD_CUST);
+       //sattr.custom_divisor = (115200/12800);
+       sattr.custom_divisor = ((sattr.baud_base)/12800);
+       if (ioctl(tty, TIOCSSERIAL, &sattr) < 0)
+       {
+               perror("ioctl()");
+       }
+       cfsetospeed(&tattr, B38400); /* Should be set to this fixed value */
+       cfsetispeed(&tattr, B38400);
+       if (tcsetattr(tty, TCSANOW, &tattr) == -1) {
+               perror("tcsetattr()");
+       }
 
-       write(tty, &buff[0], 1);
 
-       cfsetospeed(&tattr, UART_SPEED);
-       tcsetattr(tty, TCSADRAIN, &tattr);
+       printf("Write break\n");
+       write(tty, &buff[0], 1); /* Write "break" */
+#if 0
+       read(tty, &buff[0], 1);
+       printf("Break read\n");
+#else
+       {
+               struct timespec sleep_time;
+               sleep_time.tv_sec = 0;
+               sleep_time.tv_nsec = ((1000000000ll * 11) / lin_break_baud);
+               clock_nanosleep(CLOCK_MONOTONIC, 0, &sleep_time, NULL);
+       }
+#endif
+
+       sattr.flags &= (~ASYNC_SPD_CUST);
+       sattr.flags |= (ASYNC_SPD_MASK);
+       if (ioctl(tty, TIOCSSERIAL, &sattr) < 0)
+       {
+               perror("ioctl()");
+       }
+
+
+       /* Save "standard" baudrate to termios struct */
+       cfsetospeed(&tattr, lin_baudrate);
+       cfsetispeed(&tattr, lin_baudrate);
+       if (tcsetattr(tty, TCSANOW, &tattr) == -1) {
+               perror("tcsetattr()");
+       }
 
        //tcsendbreak(tty, 1);   /* Break */
        //usleep((useconds_t) 50); /* Break Delimiter */
@@ -151,13 +231,21 @@ int main(int argc, char* argv[])
                return -4;
        }
 
+       fcntl(fileno(stdin), F_SETFL, O_NONBLOCK);
+       printf("Press enter to terminate.\n\n");
+
        /* Configure UART */
-       set_input_mode(tty, UART_SPEED);
+       set_input_mode(tty, lin_baudrate);
 
        while(1) {
+               char c;
+
                send_header(tty);
                sleep(1);
-       }       
+
+               if (read(fileno(stdin), &c, 1) > 0)
+                       break;
+       }
 
        reset_input_mode(tty);
        close(tty);