Xiao Exapansion board w/Xiao BLE, shorted 3.3V power on XEB

[leroyle]

Sometime back (Feb 2022) we were seeing an issue with some of the Xiao Expansion boards appearing to short out the on board 3.3v regulator when plugging in the Xiao BLE.

Here is one such thread from Feb 2022

Is my XIAO Expansion board defective? or repairable?

I was asked by SEEED to place this in the Forum! I just received my XIAO BLE Sense and two XIAO Expansion boards. It appears that one XIAO Expansion board is not working. Here is how I came to that conclusion. I attached new assembled XIAO BLE Sense to Expansion board 02 and I could not attach to it via Computer USB port. Nothing happened. I then attached the XIAO BLE Sense to Expansion board and was able to hear the common PC USB attachment sound. After pressing Reset 2x I was able to dow…

In my case I was just plugging the Xiao BLE into the expansion board, usb connector the to Xiao BLE. (no other power source, battery etc)

The modified broken boards worked for my purpose, just using the SWD interface, but now I find I’m needing to run some I2C functionality, which does not work when the Xiao pins 4/5 are connected to the broken board.

Has the expansion board been modified to help eliminate this issue? If so, is there a board rev number we should look for?

If not redesigned then it sounds like the safe bet is to not connect the Xiao BLE 3.3V pin to the expansion board. Is this the “official” answer.

Thanks

[PJ_Glasso]

Hi there,
Wow, that’s a PITA for sure.
I have had exceptional LUCK then , I used several of them ALLOT still do.
all with the SWD & JLink-Plus and 4-wires.(first row of 4)
NEVER had a failure…

Until the problem I had between the Keyboard and the Floor, I.E. “Accidently, Unintentionally, in a hurry” plugged the Xiao in with a pin left hanging out the back or front.(don’t do That!) I could feel it getting warm, Quickly removed it and that Nrf52840 sense Xiao, Kinda works It’s a goner. I hurt something it appears and uploads but No Spi or D1 GPIO NEXT!
A new replacement works as expected and the XEB works as always. YMMV

HTH
GL PJ

[leroyle]

Thanks @PJ_Glasso, i guess I will order up another but keep the 3.3 pin disconnected, assuming the expansion is powered from the 5v pin, just to be safer.