RC Receiver Not Detected by ArduPilot on VOXL2 IO Board (M0065)

[daylan]

Summary
We are unable to receive any RC input through the VOXL2 IO board when running ArduPilot. The same RC hardware works correctly when running PX4 on the same VOXL2 and IO board, which suggests the hardware and wiring are functioning properly.

System Information

• Platform: VOXL2
• IO Board: M0065 (connected via J3 RC input port)
• VOXL Suite: 1.6.3
• voxl2-io package: 0.0.3
• ArduPilot: 4.8.0-8ed7441c
• PX4: Included with VOXL Suite 1.6.3

Issue Description
When running ArduPilot, no RC inputs are detected. The receiver does not appear to communicate with the flight controller.

To isolate the issue, we booted the same hardware into PX4 without changing the wiring or receiver configuration. Under PX4, the RC receiver is detected and functions normally.

Troubleshooting Performed

• Connected the RC receiver to the J3 RC input on the M0065 IO board.
• Tested multiple RC receivers/transmitters (different models).
• Verified that each receiver works correctly when PX4 is running.
• Switched back to ArduPilot using the same hardware configuration, where no RC inputs are detected.
• Confirmed the issue is repeatable across multiple receivers.

Questions

• Is RC input through the M0065 IO board J3 port currently supported in ArduPilot on VOXL Suite 1.6.3?
• Are there any required ArduPilot parameters or VOXL configuration steps needed to enable RC input through the IO board?
• Is there a known compatibility issue between voxl2-io version 0.0.3 and voxl-ardupilot 4.8.0?
• Are there any logs or debug commands we can provide to help diagnose why the RC input is not being detected?

Any guidance would be appreciated.