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RE: bad timing of RS485 TXE when using omap-serial driver » send.c

Mihai Cristea, 07/04/2013 02:15 AM

 
#include <linux/serial.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <termios.h>

/* Driver-specific ioctls: */
#define TIOCGRS485 0x542E
#define TIOCSRS485 0x542F

/* new defines in linux/serial.h of CL provided kernel */
#ifndef SER_RS485_USE_GPIO
#define SER_RS485_USE_GPIO (1<<5)
#define gpio_pin padding[0]
#endif

/* Convert GPIO signal to GPIO pin number */
#define GPIO_TO_PIN(bank, gpio) (32 * (bank) + (gpio))


#define GATERO_UART1_RS485EN GPIO_TO_PIN(0,12)
#define GATERO_UART2_RS485EN GPIO_TO_PIN(0,13)
#define GATERO_UART3_RS485EN GPIO_TO_PIN(1,31)
#define GATERO_UART4_RS485EN GPIO_TO_PIN(1,30)


/*
* Test program for 485 control
*/
int main(int argc, char* argv[])
{
struct serial_rs485 rs485conf;
char buffer[20], buffer2[21],uartname[10];
int i, rv, opt, uartnr,gpio_txen;
struct termios my_termios, new_termios;
if (argc > 1)
{
uartnr = atoi(argv[1]);
sprintf(uartname, "/dev/ttyO%d", uartnr);
switch(uartnr)
{
case 1: gpio_txen = GATERO_UART1_RS485EN; break;
case 2: gpio_txen = GATERO_UART2_RS485EN; break;
case 3: gpio_txen = GATERO_UART3_RS485EN; break;
case 4: gpio_txen = GATERO_UART4_RS485EN; break;
default: printf("The command had out of range uartNr: Only 1 to 4 available.\n"); exit(1);
}
}
else
{
printf("The command had no other arguments. Usage: %s uartNr\n", argv[0]); exit(1);
}

int fd0 = open(uartname, O_RDWR | O_NDELAY | O_NOCTTY);

rs485conf.flags = (1<<0); //SER_RS485_ENABLED;
rs485conf.flags |= SER_RS485_USE_GPIO;
rs485conf.delay_rts_before_send = 0;
rs485conf.gpio_pin = gpio_txen;

rv = ioctl (fd0, TIOCSRS485, &rs485conf);
if (rv) {
printf("rv = %d\n", rv);
perror("unable to set IOCTL:");
}

tcgetattr(fd0, &my_termios);
my_termios.c_iflag &= ~(IGNBRK | BRKINT | ICRNL | INLCR | PARMRK | INPCK | ISTRIP | IXON);
my_termios.c_oflag &= ~(OCRNL | ONLCR | ONLRET | ONOCR | OFILL | OLCUC | OPOST);
my_termios.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN | ISIG | ECHOK | ECHOCTL | ECHOPRT);
my_termios.c_cflag &= ~(CSIZE | PARENB);
my_termios.c_cflag &= ~CRTSCTS;
my_termios.c_cflag |= CS8 | CLOCAL;
my_termios.c_cflag &= ~CBAUD;
my_termios.c_cflag |= B115200; //B115200; // B19200; //
my_termios.c_cc[VMIN] = 1;
my_termios.c_cc[VTIME] = 0;
rv = tcsetattr(fd0, TCSANOW, &my_termios);
tcgetattr(fd0, &new_termios);


for (i = 0; i < 20; i++) {
buffer[i] = 'A'+i;
}

for (i = 0; i < 1; i++) {
printf("Writing [%d]\n", i);
write(fd0, buffer, 15);
sleep(1);
}
close(fd0);
}
(1-1/2)