@scosgrove Unfortunately, there isn't a whole lot of useful documentation about that. You kind of have to look through the Qualcomm source code to get an idea of what it is doing. One idea is to use the Qualcomm mini-dm debug tool. It is included with the Hexagon SDK. If you are connected to the USB port (i.e. you can use adb) then you can use mini-dm. This will output more information from the DSP as it is running and you may see some error messages coming out when you are seeing issues with data loss.

@voxl-phoenix J19 has pins for 2 UARTs. We put GNSS on one and RC on the other. So if you are able to hook up everything correctly, configure the TBS crossfire receiver correctly, and configure PX4 correctly then it should work.

@Eric-Katzfey I will need to add the support for up to 8 PWM outputs on VOXL 2 IO board. Right now it only supports 4. You should be able to do test flights without the gimbal with 4 PWM outputs.

@TomP I have updated the documentation at https://docs.modalai.com/voxl-ardupilot/. The VOXL 2 IO board with up to 4 PWM outputs is now supported and has been tested on a quadcopter with 4 PWM ESCs. You should be able to use this for arduplane now. We are putting together our own fixed wing test platform and hope to begin testing soon.

@voxl-phoenix VOXL 2 is really not a great place to start if you are new to drones. And the best way to start with a VOXL 2 is with one of our pre-built drones like the Starling 2 (https://www.modalai.com/products/starling-2), not with a bare board. The standard place to connect RC for PX4 is J19.

@voxl-phoenix What PX4 driver are you intending to use with it? And why don't you want to attach it to the "normal" RC UART on J19?

@Jeremy-Frederick Okay, well then you will need to add support for such an external Mavlink enabled peripheral into voxl-mavlink-server. We don't currently support that.

@Jeremy-Frederick Without going through the voxl-mavlink-server source code in detail I'm pretty sure that what you want to do is not currently supported. So, some new functionality will likely need to be added to voxl-mavlink-server. What third party unit are you trying to integrate with? Does it require bi-directional traffic or does it just send out packets and not expect to receive anything?

@scosgrove PX4 runs on the Sensors Hexagon DSP (AKA SLPI, AKA SDSP). Most of PX4 runs on that DSP but there is some part of PX4 that runs on the Linux applications processor (e.g. Mavlink, logging, data manager, etc.). The applications processor portion communicates with the DSP portion via the muorb (multiprocessor uorb) module in PX4. Unfortunately, all of the details of the UART HW and drivers (including the API) are Qualcomm proprietary so we are not able to share details of that. There isn't much configuration going on though, just port number and baudrate. There is no DMA. Can you move your driver to the applications processor? If you have an add-on board with an application processor mapped UART then you could run on the applications processor.

Hi @Jeremy-Frederick @valvarez
ModalAI has not designed any power supply reference voltages on JST connectors as a REF or Power Tap Off as capable of powering servos.
If you wish to power micro-servos then please do so at your own risk. However, you may likely damage your ModalAI hardware since we do not have any back EMF/Stall/Load dump protection on any of our JST connectors.

Servos need to have their independent supply from your system battery.
Apologies we have not made that clearer in our Tech Docs.

Thanks!