# UARTs on J17

Source: https://forum.modalai.com/topic/2487/uarts-on-j17
Category: VOXL 2 and VOXL 2 Mini (https://forum.modalai.com/category/26/voxl-2-and-voxl-2-mini)
Tags: voxl-2-mini
Posted: 2023-07-25 23:22:09 UTC by Brendon
Replies: 2 · Views: 985

## Brendon · 2023-07-25 23:22:09 UTC

I'm trying to communicate with some external devices using two of the UARTs in J19, but can't find any documentation on how the physical UARTs are mapped to the tty devices.

In particular, I need to use both GNSS and ESC serial ports from C and/or as a login console.

Thanks.

## Reply by Moderator (ModalAI staff) · 2023-07-26 04:38:09 UTC

@Brendon You are likely referring to J17 on VOXL 2 Mini. That connector exposes I/O connected to the Flight DSP, labeled in that table as "slpi_proc". They will not be exposed as a tty device.

We are currently working on libqrb5165-io which will provide an API to passthrough and expose a UART to the CPU.  It could be a few weeks until a solid dev version of that is available

While waiting for that, you could look at the voxl-slpi-uart-bridge which voxl-esc-tools uses to program the ESCs from the CPU https://gitlab.com/voxl-public/voxl-sdk/core-libs/voxl-slpi-uart-bridge . That tool has only been tested in limited capacity for the ESC programming and diagnostic, but it should expose a way to use that UART.

## Reply by Brendon · 2023-07-26 05:05:35 UTC (in reply to Moderator)

@Moderator I'll take a look at that code. Can you tell me which UARTs currently are available as tty devices?

I may be able to rewiring things to use different ports while I wait.

Thanks.