7.6 UART Interface
The device provides four (4) serial ports. DEBUG is used for debugging, while UART0, UART1, and UART2 are general purpose serial ports that support 3.3 V CMOS levels. DEBUG, UAR…
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The device provides four (4) serial ports. DEBUG is used for debugging, while UART0, UART1, and UART2 are general-purpose serial ports that support 3.3 V CMOS levels. DEBUG, UART1, and UART2 support a 3.3 V external power output with a current of less than 1 A. UART0 supports a 5V0 external power output with a current of less than 2 A. The interface pin definitions are shown below.
NVIDIA Jetson Linux 35 Ubuntu 20.04
| Pin Interface | PIN 1 | PIN 2 | PIN 3 | PIN4 | PIN5 | PIN6 |
|---|---|---|---|---|---|---|
| UART0 (ttyTHS1) | 5V0 | 5V0 | RX | TX | GND | GND |
| UART1 (ttyTHS0) | 3V3 | RX | TX | GND | N/A | N/A |
| UART2 (ttyUSB0) | 3V3 | RX | TX | GND | N/A | N/A |
| DEBUG | 3V3 | RX | TX | GND | N/A | N/A |
NVIDIA Jetson Linux 36 Ubuntu 22.04
| Pin Interface | PIN 1 | PIN 2 | PIN 3 | PIN4 | PIN5 | PIN6 |
|---|---|---|---|---|---|---|
| UART0 (ttyTHS2) | 5V0 | 5V0 | RX | TX | GND | GND |
| UART1 (ttyTHS1) | 3V3 | RX | TX | GND | N/A | N/A |
| UART2 (ttyUSB0) | 3V3 | RX | TX | GND | N/A | N/A |
| DEBUG | 3V3 | RX | TX | GND | N/A | N/A |
UART Function Test
Test Equipment
Power adapter, Allspark-Orin NX main unit, and self-made RX/TX loopback cable
Test Objective
Test the functionality of the UART-related circuitry
Test Procedure
UART0 and UART1 Test
-
Tip
Use the superuser: sudo su
- Connect UART0 to UART1 according to the pin definitions in the figure below.

- Enter the command to become the superuser.
- sudo su
- Enter the command below.
- serialTest /dev/ttyTHS1 /dev/ttyTHS0
- The output shown below indicates that the UART0-to-UART1 transmit/receive loop test passed.

UART0 and UART2 Test
- Connect UART0 to UART2 according to the pin definitions in the figure below.

- Enter the command to become the superuser.
- sudo su
- Enter the command below.
- serialTest /dev/ttyTHS1 /dev/ttyUSB0
- The output shown below indicates that the UART0-to-UART2 transmit/receive loop test passed.

