COM port not showing on Platform IO

A student of mine cannot upload her code to an EGLOO dev board. She also tried uploading a sketch from the Arduino IDE and it wouldn’t recognize any port. The pulldown menu for tools on the Ardiuno IDE has Port greyed out.
I checked her device manager, and there is no indication that it recognizes the Ardiuno COM port.
When running Platform IO, I checked the platform.ini file and it looked correct.
She has Windows 10 Home installed as her OS.

Any suggestion of where to start troubleshooting would be appreciated,


It is an ATMEGA 2560 board purchased via Amazon from EGLOO

Unless the board itself is dead/not communicating, I’m wondering if the USB cable is one of those which onlynhas power connections? It needs to be a 4 wire “data” cable.

Swap the cable for one that works elsewhere and see?

Other than that, plug it into a Linux computer with dmesg --follow running and check that the comms chip is being recognised. I don’t know how tha bworks on Windows though. Possibly there’s an unknown device in device manager? Maybe the driver hasn’t been loaded/found?



The board has the power light and the L light on , but no TX and RX. I wish I could swap the cable, because that is the easiest thing. We are all doing this remotely due to COVID, so it makes it harder to try swapping out cables and boards. i suggested that she order a new cable and new board ($20 from Amazon), so that will be something that she will try. There isnt an unknown device found in her device manager. We took a snapshot of her device manager list. There is an “other” device that shows up that is related to bluetooth device and her USB ports work on with other devices such as a mouse. Here is a upload of an image of her device manager list
device manager list_no com port

I have a similar kit with no issues as do other students. It might be the cable. I don’t think there is a way to determine if the cable is a 4 wire data cable by inspecting it?

Thanks for the suggestions!

She did plug her board and cable into another older and slower laptop that she had and the Arduino IDE recognized the port but it timed out when uploading the sketch to the board. Also Platform IO still didn’t recognize any COM port on the older laptop.

Sounds about right! I plugged my Mega2560 R3 Clone into my laptop and that’s what mine does as well. I would say that the board is ok based on that. You only get TX and RX when the USART is working/in use. After a reboot, the Arduino Language/System disconnects the RX and TX pins and disables the USART. Those two pins become D0 (RX) and D1 (TX) on an Uno, but are RX0 and TX0 on a Mega 2560 R3 as that little beauty has three Serial interfaces. (Apologies if Grandma already knows how to suck eggs!)

Covid is an effing nightmare. Apologies for language. I can cope with it most of the time, being a “hermit” (or so my wife says!) but she’s a sociable person and it’s driving her nuts. I think it will be quite a while before we are “normal” again.

I mentioned running dmesg --follow i=on a Linux device. This is what my laptop reports:

[  878.680035] usb 5-2: new full-speed USB device number 3 using uhci_hcd
[  878.900114] usb 5-2: New USB device found, idVendor=2341, idProduct=0042
[  878.900118] usb 5-2: New USB device strings: Mfr=1, Product=2, SerialNumber=220
[  878.900121] usb 5-2: Manufacturer: Arduino (
[  878.900123] usb 5-2: SerialNumber: 85535303536351E04032
[  878.902218] cdc_acm 5-2:1.0: ttyACM0: USB ACM device

I suspect it’s not a genuine Arduino, regardless, but I can see that plugging it in has registered in the system. Unfortunately, I’m not able to tell you how to do this on Windows. :frowning_face: Unless USBDVIEW helps? View any installed/connected USB device on your system - I assume your student has privileges etc to install software?

Alternatively, can she access the registry? HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\DeviceClasses is apperently the place to go. I would look that up before plugging in the board and see what/how many entries there are. After plugging in the board, F5 (I think) to refresh and see if anything comes up.

If so, I would suspect a missing driver for the comms chip on board the Mega 2560, if not, 99% certain it’s the cable. (Or, a duff comms chip!)

Not by looking at it - unless it’s transparent and you can count the 4 wires. However, does she have a smart phone/eReader/Kindle/music player that she knows works? She could use the cable to test it and see if the device is recognised? Unless Apple are using proprietary connectors of course. I’m an Android man myself.

Actually, does she have a Kindle? That lead is definitely a data lead. Try swapping.



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