Hi,
I am using a prolific tech USB-to-serial converter on linux kernel version 2.6.35.
I wrote a userspace program to enable/disable RTS line which is working fine with
standard serial port like ttyS0 and ttyS1.
But when I used the USB-to-serial port (ttyUSB0) to enable/disable the RTS line,ttyUSB0
is not able to do that as well as some times gives
pl2303_ttyUSB0 : pl2303_open-failed submitting read urb -error 22.
Attached is the userspace application and kernel log is also given below,
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_open - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x40:0x1:0x8:0x0 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x40:0x1:0x9:0x0 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - data bits = 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - baud = 9600
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - stop bits = 1
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - parity = none
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x21:0x20:0:0 7
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x40:0x1:0x0:0x0 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_open - submitting read urb
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_open - submitting interrupt urb
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x540b
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x540b
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x5402
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x5402
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - data bits = 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - baud = 9600
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - stop bits = 1
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - parity = none
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x21:0x20:0:0 7
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x40:0x1:0x0:0x61 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_tiocmget (0)
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_tiocmget - result = 6
/home/teleset/Desktop/USB-Serial/pl2303.c: set_control_lines - value = 3, retval = 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_tiocmget (0)
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_tiocmget - result = 6
/home/teleset/Desktop/USB-Serial/pl2303.c: set_control_lines - value = 1, retval = 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x5402
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x5402
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - data bits = 8
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - baud = 9600
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - stop bits = 1
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_set_termios - parity = none
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x21:0x20:0:0 7
/home/teleset/Desktop/USB-Serial/pl2303.c: set_control_lines - value = 3, retval = 0
/home/teleset/Desktop/USB-Serial/pl2303.c: 0xa1:0x21:0:0 7 - 80 25 0 0 0 0 8
/home/teleset/Desktop/USB-Serial/pl2303.c: 0x40:0x1:0x0:0x0 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl (0) cmd = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_ioctl not supported = 0x5401
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_close - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_close - shutting down urbs
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_read_bulk_callback - port 0
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_read_bulk_callback - urb status = -2
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_read_bulk_callback - port is closed,
exiting.
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_read_int_callback (0)
/home/teleset/Desktop/USB-Serial/pl2303.c: pl2303_read_int_callback - urb shutting do
Thanks-
Raj
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
static struct termios oldterminfo;
void closeserial(int fd)
{
tcsetattr(fd, TCSANOW, &oldterminfo);
if (close(fd) < 0)
perror("closeserial()");
}
int openserial(char *devicename)
{
int fd;
struct termios attr;
if ((fd = open(devicename, O_RDWR)) == -1) {
perror("openserial(): open()");
return 0;
}
if (tcgetattr(fd, &oldterminfo) == -1) {
perror("openserial(): tcgetattr()");
return 0;
}
attr = oldterminfo;
attr.c_cflag |= CRTSCTS | CLOCAL;
attr.c_oflag = 0;
if (tcflush(fd, TCIOFLUSH) == -1) {
perror("openserial(): tcflush()");
return 0;
}
if (tcsetattr(fd, TCSANOW, &attr) == -1) {
perror("initserial(): tcsetattr()");
return 0;
}
return fd;
}
int setRTS(int fd, int level)
{
int status;
if (ioctl(fd, TIOCMGET, &status) == -1) {
perror("setRTS(): TIOCMGET");
return 0;
}
if (level)
status |= TIOCM_RTS;
else
status &= ~TIOCM_RTS;
if (ioctl(fd, TIOCMSET, &status) == -1) {
perror("setRTS(): TIOCMSET");
return 0;
}
return 1;
}
int main()
{
int fd;
char *serialdev = "/dev/ttyUSB0";
fd = openserial(serialdev);
if (!fd) {
fprintf(stderr, "Error while initializing %s.\n", serialdev);
return 1;
}
setRTS(fd,1);
usleep(10000);
setRTS(fd, 0);
closeserial(fd);
return 0;
}
