# VOXL2 Mini J10 UART

Source: https://forum.modalai.com/topic/2925/voxl2-mini-j10-uart
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2023-12-06 13:43:01 UTC by Shaun Cosgrove
Replies: 3 · Views: 1179

## Shaun Cosgrove · 2023-12-06 13:43:01 UTC

After flashing  the latest system image for the VOXL2 Mini (with no subsequent modifications apart from wifi setup), I cannot get the J10 Uart RX (sending to the mini) working. TX (sending from the mini) works as expected. Is there some configuration / parameter that I am missing or any suggested way to debug this?  I will try a new mini board in case there is a hardware issue. Thanks!

## Reply by Shaun Cosgrove · 2023-12-06 19:18:33 UTC

Scoping the RX line, there is an 80mV p2p signal on the RX (to VOXL2 Mini) and a 3v3 on the TX. 

Is there a pull-down configured for the RX pin or some other configuration that could explain this? Is it possible to change this during runtime or will it require rebuilding the system image?

## Reply by modaltb (ModalAI staff) · 2023-12-07 19:59:33 UTC

There's a directional level shifter on the RX pin, and it seems like our default state isn't what I have documented, and I need to investigate that!

As temporary work around, you can set the pin state with onboard utility:

``` 
 voxl2-mini:/$ voxl-gpio -w 67 0
```

For others, you can check loopback if you have it (between pins 4/5 of J10):

```
voxl2-mini:/$ qrb5165io-uart-test -d 0
 [INFO]: success!
```

Sorry for the confusion!  We'll fix.

## Reply by Steve Turner · 2023-12-07 22:01:03 UTC (in reply to modaltb)

@modaltb Thankyou so much for the quick eyes on this!
We owe you some beers!