My Xiao NRF52480 Sense died after I had spent a couple hours soldering on a battery and some 3 pin connectors to the gpio pins. After I finished soldering I was poking around with the multimeter checking the continuity of soldered pins and then the whole thing died. Even after removing all the wires/battery and resetting it still doesn’t function. Any idea what I did that can cause this? Would shorting the battery pins do this?
Thanks in advance,
Colin
Disconnect all wires, including those for the battery and trimmers, then connect the XIAO to your PC via USB and try running Blink.ino. Does it work?
Thanks for the response. No it doesn’t appear as a USB drive any more even after pressing the reset button twice, nor do any leds flash from previous firmware installs or upon reset.
The XIAO may have been damaged when the battery came into contact with the I/O pins during soldering, but please check carefully once again to make sure the XIAO pins aren’t shorting to adjacent pins or pads.
Pin 0 may be a bootstrap pin… try something else
Ya I’m pretty sure it’s fried. The 3.3v to ground measures 0.6v on the bad one and it’s 3.3v on the good one when I plug them into a USB power source. I don’t see any evidence of shorting from the soldering, but it’s entirely possible the battery came into contact with the io pins while I was fumbling with the multimeter. Reading more about continuity testing, I should only be doing this for circuits with the power source disconnected so I will make sure I don’t wire up the battery until after I have tested the other circuits next time. Unfortunately with the wiring routes and the placement of the battery terminals on the non-plus Xiao’s it’s very hard to solder the battery after the other wires are in place but at least now I have had some practice:) Thanks for all the responses.
Here is an example of soldering to a battery pad. The trick is to use relatively thin leads. After soldering, I secure the leads with adhesive to keep them from moving.
Hi there,
And welcome here,
So from your schematic , I see you have one side of the pot connected to GND , the other is connected to pin 2 and also 3.3v with the wire across the two. SO when the pot is turned all the way, in one direction it would be a dead short. 
Why pull that pin up?
HTH
GL 
PJ 
I am assuming that is just a bad schematic… I saw that too… but i saw no reason someone would do that….
