Flashing Jetson -- Is it compulsory to use USB to Serial converter ?

Hello all,

When flashing Jetson, is it compulsory to use USB to Serial converter ?

Thank you

The only cable you need to flash the TK1 is a micro-USB-to-USB cable.

So I will never need a serial converter , if i have monitor and keyboard (unless something goes wrong)?

Correct.

You will normally never need to use the serial port… until you really do! :)

If you do need to use the serial port what are the UART parameters, i.e. baud rate etc.?

115200, 8N1.

If your Jetson is working (ie: can boot to a Linux command-line or to a graphical desktop) then you don’t need a USB to Serial. You can use a HDMI monitor & USB keyboard+mouse, or access it remotely (such as by opening an SSH terminal through your network from another computer). And to flash the device you can use the included micro-USB cable.

The only time you might need a USB to Serial converter is if your Jetson isn’t booting up properly at all, so none of the above options work at all, so then you would use a USB to Serial since that will often work even if something more serious is broken on your device. (If even a USB to Serial converter doesn’t work then you’re really in trouble and probably need an Oscilloscope or Logic Analyzer or a new Jetson TK1!).

Is it possible to access Jetson linux console from RS232? I flashed jetson with latest jetpack. I connected RS232 but I cannot see anything on the serial terminal.

My serial configuration is 115200,8,n,1 no hardware flow control.
I couldn’t find a document regarding this.

Thank you.

If you’re not seeing console output and your settings are correct then it might be your cabling.

Make sure you’re using a null modem cable or equivalent.

If you have access to a multimeter check the voltage on pins 2 and 3 with respect to ground which is pin 5. Any time you connect two RS232 devices one will transmit on 2 and listen on 3, and vice versa for the other. The transmit pin is typically a negative voltage when idle. So disconnect the cable and measure the female and male connectors. One should have pin 2 as negative and the other should have pin 3 negative.

This way you are not guessing if you need a null modem cable or not. A null modem will swap pins 2 and 3. Some other pins are also swapped but if you don’t use hardware flow control the other pins are ignored.

You might need to put a small wire (a through hole resistor lead works great for this) into the female connector to gain access to the pin. And you’ll need good eyes to see the tiny pin numbers typically molded into the plastic that holds the pins.

Take care that the RS232 port on Jetson TK1 uses the full voltage (ie: roughly -25V and +25V signals) like the traditional RS232 ports had, but these days a lot of devices use TTL-level serial ports (0V and 5V signals), so it is possible you are using a TTL-level USB-to-Serial converter but for Jetson TK1 you need a full voltage USB-to-Serial converter. eg: I use http://www.amazon.com/Tripp-Lite-USA-19HS-High-Speed-supports/dp/B0000VYJRY

I found the error. It was because of the gender changer. Then I manually connected the ports using wires as a null modem. Then it worked…

Thanks all …