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Jetson Is Not Working — How Can I See the Error Logs?
If your Jetson device isn’t powering on properly or seems unresponsive, one of the most effective ways to diagnose the issue is through UART debugging.
UART (Universal Asynchronous Receiver/Transmitter) is a widely used serial communication protocol for interfacing between electronic devices. Developers often use UART for debugging by connecting a UART module to their device, enabling them to send real-time debug messages (e.g., variable values, program flow) to an external terminal. Since UART operates asynchronously—without a shared clock signal—it is relatively simple to implement and ideal for embedded system debugging. This document explains how to perform UART debugging on Jetson modules using a USB-to-TTL converter.
This document explains how to perform UART debugging on Jetson modules using a USB-to-TTL converter.
Required Materials:
- Jetson Developer Kit or AI Edge Kit
- Jumper wires
- FTDI or USB-to-TTL Serial Converter
- Ubuntu-based host PC for debugging
The steps below are demonstrated using a Jetson Nano Developer Kit, but they are applicable to all Jetson platforms.
1. Wiring
Identify the RXD, TXD, and GND pins on your FTDI or USB-to-TTL module. Connect them to the Jetson UART pins using jumper wires. Note that the connections must be crossed (TX ↔RX):
| Jetson | FTDI |
|---|---|
| RXD | TXD |
| TXD | RXD |
| GND | GND |
Connect the USB side of the converter to your host PC, but do not power the Jetson device yet. Power will be connected in Step 8.
2. Install Minicom
Minicom is a terminal emulator used to read the UART output.
3. Identify the Serial Port
Use the dmesg command to monitor kernel messages and identify the device node (e.g.,/dev/ttyUSB0) when the converter is plugged in:
Look for a line similar to:[ 123.456789] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0
Note the device path: ttyUSB0.
4. Configure Minicom
In a new terminal window, run:
Select Serial Port Setup
Set the following:
Serial Device /dev/ttyUSB0
Bps/Par/Bits 115200 8N1
Hardware Flow Ctrl Yes
Press Esc, then choose Save setup as dfl, and exit.
5. Start Minicom
Start minicom with the saved default configuration:
You should now see a blank terminal screen waiting for serial input.
6. Power the Jetson Device
Now connect power to your Jetson. As it begins to boot, UART messages will start to scroll in the Minicom window. You can observe boot logs and error messages in real-time.
Once the boot sequence finishes, you can use these logs to identify and diagnose system
issues.