# Using VOXL ESCs with PX4

Source: https://forum.modalai.com/topic/1263/using-voxl-escs-with-px4
Category: General Questions (https://forum.modalai.com/category/2/general-questions)
Posted: 2022-08-29 18:59:07 UTC by Suvasis M
Replies: 7 · Views: 1151

## Suvasis M · 2022-08-29 18:59:07 UTC

hi 

I am building my drone, I want to use "VOXL ESCs with PX4" for my drone. Is there any documentation on how to use VOXL ESCs with Nvidia processors.e, the los setup?

Thanks.
suvasis

## Reply by modaltb (ModalAI staff) · 2022-08-29 19:03:28 UTC

Hi @Suvasis-M ,

The source code for the driver is here:
https://github.com/PX4/PX4-Autopilot/tree/main/src/drivers/actuators/modalai_esc

If you have access to a UART port on the nvidia, it's likely you can port this driver over fairly easily but this isn't something we've done.

Thanks!

## Reply by Suvasis M · 2022-08-29 19:11:44 UTC

hi,

I have Jetson AGX orin processor, it has UART on M.2 KeyE. Ok then, looks like I can port the driver. Is there any ubuntu OS specifics? I have 20.04 version.

Thanks.
suvasis

## Reply by modaltb (ModalAI staff) · 2022-08-29 19:38:47 UTC

Hi @Suvasis-M ,

Its setup in the native form for Nuttx RTOS, which starts the driver up as a task, and has some specific PX4/Nuttx related calls, but you should be able to find equivalents for Ubuntu, so I don't believe there would be any blockers.

We create a packet and send it here:
https://github.com/PX4/PX4-Autopilot/blob/main/src/drivers/actuators/modalai_esc/modalai_esc.cpp#L1120

and parse feedback here:
https://github.com/PX4/PX4-Autopilot/blob/main/src/drivers/actuators/modalai_esc/modalai_esc.cpp#L1151

## Reply by Suvasis M · 2022-08-30 21:35:47 UTC

@modaltb said in [Using VOXL ESCs with PX4](/post/5870):
> PX4/Nuttx related calls,

hi,

Which are the PX4/Nuttx related calls from the actuator?

Thanks.
suvasis

## Reply by modaltb (ModalAI staff) · 2022-09-01 16:17:44 UTC

You should be able to get by with standard POSIX stuff like open/read/write.

On our DSP, we had to get rid of a `poll` that was being used and we have some delays in place instead.

## Reply by Suvasis M · 2022-09-05 18:01:16 UTC (in reply to modaltb)

@modaltb 

hi,

Where is the DSP code? Is it exposed?

Thanks
suvasis

## Reply by modaltb (ModalAI staff) · 2022-09-06 16:18:47 UTC

We have the full toolchain and setup dockerized here: https://gitlab.com/voxl-public/rb5-flight/rb5-flight-px4-build-docker

Following that setup, you will install the Hexagon SDK which provides more info on the lower level stuff.

But, the PX4 code as shown above is what runs on the DSP.