@robski I tried multiple cables. Every USB-A to USB-C cable failed, some of which I had used in the past for data transfer. I am only using 1 cable: USB-C to USB-C

@ajb2k3 To clarify: are you saying that somewhere in the Core3SE documentation it says that USB-A is power only? Could you link that or point me to it? I clearly need to dig into the hardware a bit more :)

@Juraj I can share my issue and solution using an M5Core3SE and a Win11 computer.

When I connected the M5 to the USB-A port on the PC using a USB-A to USB-C cable, I got power, but no COM ports.

When I connected the M5 to the USB-C port on the PC (using a USB-C to USB-C cable), BOOM: COM port.

I haven't dug into it to see particularly why (best guess right now is the M5 connection uses both the legacy USB 2.0 connection as well as the SuperSpeed connection: one for the terminal and one for the M5 program data stream?)

Hope this helps.

We have been exploring the M5Stack to standardize on for automated board-level testing, and have three sets of fixtures designed around the modular scalable M5Stack Core2 and CoreS3. The fixtures include the U097 4-relay module connected through the Groove port, or through a U040-B I2C expansion hub.

Unfortunately, we have experienced multiple failures of the U097, characterized by relay 1 not engaging wen energized. This has occurred with one U097 out-of-box and two during fixture verification. Root-cause analysis of the U097 seems to indicate mechanical sticking of the LCSC 932-5VDC-SL-AH relay: if the relay is removed and the coil directly energized there is still no continuity between the switch pins, but if the relay outer case is removed it functions as expected.

The relays are being used to switch signals well within their capabilities (5V, 5-50mW).

Is this a known issue? I saw another user who had an "old" and "new" U097, where the old one worked fine and the new one did not. Has something changed?