Pixhawk4: duplicate/multiple COM Ports upon connection? Why not only one?

Hardware Pixhawk family
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1

Hello everyone,
I’m encountering an issue with my Pixhawk4 where upon connection, two COM ports (e.g., COM4 and COM5) appear in my system, despite only the Pixhawk4 being connected. This is causing confusion and hindering a smooth connection. Despite multiple attempts, including factory resets, reinstalling software via Mission Planner (MP), trying different PCs and cables, the problem persists. I’m seeking assistance from the community to determine if there are specific settings, software solutions, or patches that can address this problem.

Thank you for your support.

Warm regards,
Spy

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Use the COM port where it says “ArduPilot MAVLink” and not “ArduPilot SLCAN” in the windows device manager.

I also see these two COM ports whenever USB is connected, but I don’t have trouble connecting to the FC with MP.

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Hello, thank you for the response. Indeed, they appear identical in the Windows Device Manager except for the number, for example (COM 3 and COM 4). Only when connecting in Mission Planner, COM 3 requires a connection via Mavlink and that takes only a few seconds, while on the second port COM 4, it serach for some data and taking almost 30 seconds to connect. Does this mean that the first port (COM 3) is the “MAVlink Port”?

Would it be possible to explain the difference between “ArduPilot MAVLink” and “ArduPilot SLCAN”?

4

For me it looks like this:

image

Now that I think about it, for me “MAVLink” was always on the first COM port.

As far as I know, SLCAN is a means to communicate with UAV-CAN devices through serial port, similar to BLHeli passthrough for ESC configuration.

1 Like
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This wiki page may help: Connect Mission Planner to AutoPilot — Copter documentation

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"Autopilots equipped with F7 or H7 processors and featuring CAN interfaces utilize firmware that presents two USB interfaces: one for the regular MAVLink connection, and another for SLCAN serial connections to the CAN interface for configuration and firmware updates. This configuration is referred to as a composite USB device.

By default, the MAVLink USB interface is labeled SERIAL0, while the SLCAN USB interface corresponds to the highest SERIALx port the board presents."
(Connect Mission Planner to AutoPilot — Copter documentation)

Therefore, since the Pixhawk 4 is a flight controller built on the STM32F765 platform, it falls into the category of F7 FCs. Thus, this behavior appears to be standard.