JTAG_UART with no PC make trouble

Thanks Kelly for your replay.

About the TIOCSTIMEOUT and TIOCGCONNECTED you can fined it here in Intel publishing : https://www.intel.com/content/www/us/en/docs/programmable/683130/23-1/ioctl-operations-43708.html

About The link to ioctl() I have see it but the problem is the inputs and output of it. The first parameter id int fd, which is not the common use of FILE* fd but use a number from 0 till 32. But I don't know which one is refer for sdout. I was gust it is 1 by looking on the define of using it where I think 0-> stdin, 1-> stdouit, 3- stderror but I am not sure.

What I try to do is looking for HOST connectqdisconnect on the JTAG_UART so I try this:

int state;
int err;
int device_num=1;

err = ioctl (device_num, TIOCGCONNECTED, &state);// check if HOST connect to the stdout
if(state == 0)
{
printf("\nNo HOST UART found\n");
fclose(stdout);
printf("\nNo HOST UART found fclose was operate\n");

}

but it didn't detect.

SO I add some delay before by thinking it need more time from powerup. I also make some loop of 10 cycles to make some check but all didn't help.

Only when I add the timeout parameter:

int time =1;

err = ioctl (device_num, TIOCSTIMEOUT, &time);// set Timeout for stdout as JTAG_UART

it start to detect, but it take for every print 1 sec to wait and it is to much for me.

I need that immidutly when there is no HOST to cancel the printing.

Also the function fclose(stdout); which is common in C didn't work and it continue to make print to the JTAG_UART. Maybe there is a diffrent command or define I can use dynamicly to stop printing if no host is present.

I didn't understand what is the work arrount suggest in the link I add? They point to be sure there is a timer attach to the default driver. I check it (see attach) and it is look there is a timer (sys_tck)timer) So I think I use one. If it is not the place to look for the attach time or if there is a need to change the default driver please let me know.

Maybe there is other source that can handle the JTAG_UART problem without attach host?

Thanks

Bar.