UART issues with Jetson Nano

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

Hi all,

I’m currently trying to connect an XBee device to the Jetson Nano using UART on the J41 header. I’ve run the command below to disable nvgetty.

systemctl stop nvgetty
systemctl disable nvgetty
udevadm trigger

When the UART is not connected to anything, I tried running my script to capture the UART signal using an oscilloscope and the data looks good (refer image1 below)

working
working4032×3024 795 KB

Image 1^

Everything looks good to me, however, once I have the XBee device connected to the UART (I did connect the 3.3v and ground to the nano as well) the data just goes crazy. Ideally, when no data is being sent, the UART line should be holding the 3.3v high all the time, but once the XBee device is connect it just goes haywire (refer image2&3).

weird
weird4032×3024 945 KB

weird_zoom
image 2 & 3 ^^

I’ve got no idea why as this is happening, both device UART is working perfectly fine when test individually, but it doesn’t work when connected. Hopefully, someone has some idea as to why this is happening.

3

hello nicholas.leong,

may I know what’s the connection setups between XBee device and Jetson-Nano, may I know which pin you’d used.
thanks

4

Here’s the diagram for the connection. All of the pins are located on J41 header on the Jetson Nano

image

5

hello nicholas.leong,

please note that uart baudrate settings is 115200/8n1, thanks

6

Yeap, that’s the baudrate I set it to as well. Same issue

8

@JerryChang

All fixed, it was just a wiring issue where the TX pins where shorted.