Jetson TK1 board - Serial console Output is not coming properly

Hi All,

In U-Boot, serial console output is not coming properly and initial Linux boot messages are not coming, i.e. it shows the garbage values at this booting time.

Before and after Linux login prompt, the serial console works fine, i.e. gets the input from user and outputs the cmd.

I am using Tera Term software. Please help.

Speed is set to 115200, 8 bits, 1 stop bit, no parity. For some of the output to be correct, the speed is probably already set correctly. If you have the settings available see if you have CTS/DTS flow control. Note that there is a tiny amount of “garbage” text during u-boot load, but that text is only a tiny bit of one line…the rest should be good. Flow control would help as cable lengths increase or noise in the environment gets in the way.

This configuration is not working out. The problem may be something else, not the baud rate config.

What kind of cables and/or adapters are you using? For example, regular serial cable won’t work, it needs to be a NULL-modem cable. If there is a USB serial UART involved, power may need to be applied once before it works.

Yes. It is null-modem cable.
Yes. USB-Serial UART is involved.
power may need to be applied once before it works. What is the meaning of it?
Installed L4T-2.0, in directory Linux_for_Tegra_tk1/bootloader, fastboot.bin and u-boot.bin binaries are
available, programmed these files and in board, serial output is garbage values.

Could not find out the reason for this? Please help.

Some USB to serial converters do not work properly.

Symptoms : garbage text appeals during Jetson boot up then suddenly text is correct.

Agreed with @GE_Chen…many serial UART cables just don’t work. FYI, here’s one I use which is well-behaved:

Even if well-behaved, power on most of those serial UARTS is supplied by the host, but may have some kind of “detect” for target and “sleep” when not in use. So if power is on your host, the UART is powered…but is it sleep mode or active? There may be cases where it helps to do this in order:

  1. Run serial UART on host...power it up.
  2. Run the target board.
  3. Reboot the target JTK1 momentarily, or unplug/plug the JTK1 power, or remove/add the 9-pin connector connection.

If this fails you may just need to get a different brand of serial UART. Even if the serial UART is not the issue, you’d need to do that to rule it out.

Thanks a lot.

The problem is USB-Serial Converter. Just tried with plain serial null modem cable. Then output is coming properly.

Initially I did not believe that the USB-Serial converter is the reason, since this converter was working fine with other boards.

Now I can proceed further. Thanks!