MattewM,
Been trying to get back in for weeks. password reset issue. (the seeed store and their forum have different password systems)
So I found that my D2 pullup does work, when I can get the compiler to finish (another story to follow).
Also my D1 pullup now does not work at all, I have to add a pullup for it, and my D0 port is stuck at a hard low no matter how I program it.
These all worked OK when I first got the board, and was just struggling with the compiler. (but that is another story).
I have been an engineer designing computer and avionics boards for 40 years. I know how to handle and use such boards. I think these little guys are just fragile, maybe from ESD, or something else. I do not know what. Maybe substandard silicone die in their assemblies. Not sure why they have a metal top, but it would make good protection for sensitive parts, and they could wire-bond parts to the PCB and cover them without plastic encapsulation to save a little too. But if they are going to continue to be so fragile or short lived, seed will not and should not stay in the business.
Have you tried another unit to see if it does the same thing with your D2? My second unit is fine.
I found along the way that I had to reinstall all Seeed’s drivers from scratch on a fresh install of the latest Arduino IDE (and make the install portable because of execution restrictions at work and how the seeed extensions to the IDE wanted to run .exe code out of the AppData hidden folder).
I find their extension continues to be very unstable. Compiles only complete 10% of the time. They just hang up with arduino-builder.exe processes languishing that must be manually ended to try to start things over. This statement in a small .BAT file helps: taskkill /im arduino-builder.exe /f in case you or anyone else needs it too.
I have none of these issues with compiling when I switch boards to a standard arduino uno and run the exact same code.
I would like to see seeed fix their compiler extension and come up with less fragile sillicon. I love the XIAO’s small size, big capability, and comfortable price. I just wish it was not so frustrating to try to use. I had big plans for them, but am rethinking that idea.
And I must say I looked into the hardware spec for the M0+ and it should have the ability to apply pullups on all the IO pins. If anyone at Seeed says otherwise then it may be due to issues again with their compiler extension or the quality of the silicon they are selling, and not any limitation in the processor they advertise they are using.