TMDSICE3359: TMDSICE3359 ttyS0 3Mbaud

Hi Fed,

Which version of the TI Processor SDK release do you use?

Typically uart0 is used as the Linux console on AM335x, but sounds like you use uart0 for your application, then which uart port do you use for the Linux console?

What other uart ports have you enabled in device tree?

SDK 6 

Linux console use ttyS3. 

other uart's not used.

Do you mean "Processor SDK Linux 6.0" which was released in 2019, or "AM335xSDK 6.0" which was released around 2013? The former uses kernel v4.19.x, while the latter uses kernel v3.2.

kernel 4.19.94 

Hi Fed,

Can you please explain the details how you run the test and what you observed? I don't have a ICE board, but I think I can try to reproduce the issue on Beaglebone Black once I have all the details.

Initialize

cfsetospeed(&tty, B3000000);

tty.c_cflag = (tty.c_cflag & ~CSIZE) | CS8;
tty.c_iflag &= ~IGNBRK; //disable break processing
tty.c_lflag = 0; //no signaling chars, echo, canonical processing
tty.c_oflag = 0; //no remapping, no delays
tty.c_cc[VMIN] = 0;
tty.c_cc[VTIME] = 0; //
tty.c_iflag &= ~(IXON | IXOFF | IXANY); //shut off xon/xoff cntrl
tty.c_cflag |= (CLOCAL | CREAD); //ignore modem cntrls, enable reading
tty.c_cflag &= ~(PARENB | PARODD); //shut off parity
//tty.c_cflag |= parity;
tty.c_cflag &= ~CSTOPB;
tty.c_cflag &= ~CRTSCTS;

cfmakeraw(&tty);

if (tcsetattr(fd, TCSANOW, &tty) != 0)
{
printf("error from tcsetattr!\n");
return;
}

Reading

fd_set read_fds;
FD_ZERO(&read_fds);
FD_SET(fd, &read_fds);
//printf ("e1\r\n");
write (fd,"0",1);
if (select(fd + 1, &read_fds, NULL, NULL, NULL))
{
printf ("e2\r\n");
int ret =read(fd, &tmp, 1);
//printf ("ret=%i 0x%x\n",ret,tmp);
if (ret >=0) printf ("%c",tmp);
}
}

The problem, because calls read () in endless cycle.

Please try the following test instead of your program.

root@am335x-evm:~# stty -F /dev/ttyS0 -echo 3000000
root@am335x-evm:~# cat /dev/ttyS0

freeze in execution...

But possible terminate it via Ctrl+C.

freeze in 1 command

Do you mean the console freezes when running the first command 'stty ...'?

Please ensure the UART sender doesn't send data until the first command finished.

"Do you mean the console freezes when running the first command 'stty ...'?"

I mean that no return in command string. After CTRL+C i can type new command.

After your advice (about sender, which no sending data), first command successfully completed, but reading process (second command) print unprintable symbols ususally. 

Do you mean the received data do not match with the original? What data are you sending?

At now reading process correctly read first first 48 byte , and stop reading process. I send binary 0,1,2,3 .......

You are sending binary 0,1,2,3 which are indeed unprintable symbols, so it is expected that you observed it on AM335x board.

You are rigth. The next question why program read first only 48 bytes ?