Xiao 2040 -pins do not go fully into the socket of the expansion board


I bought a Xiao 2040 and the expansion board:

However I cannot pull down the Xiao 2040 pins into the socket. There are 4 connectors of some kind which doesn’t allows that. Attached is a picture for your reference. Can someone tell me how this can be done? I am pretty new to micro controllers.

you are putting it on the wrong end


I am sorry I do not follow you…
The Xiao 2040 is oriented with its power connector exactly same way as you show.
There are four pins in front of the expansion board which do not allow the Xiao 2040 to completely be pulled down in the front area of the sockets.

You have soldered the header on the Seed Studio board the wrong way. The black plastic bit on the header goes under, not on top. The short pins are the ones you solder to the board.

Please look at the pins. The short ones are up as you mentioned and the long part of the pins is below.

It should be like this. You insert it into the board from underneath. Short pin side up, long pin side down. The short pins get soldered on the top side of the board.


I got it. I put the small headers first into the sockets then pushed the Xiao 2040 into the small pins.
It works now. Thank you for patience with me.

Ok, you hadn’t soldered it yet? Thats good and bad. You’re going to need to solder the header on for that to be a reliable setup.

Glad to help. We all had to learn the ins and outs at some point. I’ve had my fair share of “that’s not right?” moments.

Do you know by any chance what battery takes the expansion board? I assume is one of those round batteries used in scales.

I actually will solder it. But that’s one of my areas I lack skill. I rather look at a video how to solder properly. I am new to these things but at least from programming perspective I should be fine since I am a software developer.

The RTC battery is a CR1220.
The 2 pin JST battery connector takes a 3.7V Lithium Battery.

  • Lipo Battery Charging: JST2.0mm standard lipo battery connector and battery management system, supports both USB and lipo battery power supply, and easy onboard battery recharge.
    Do not connect alkaline batteries to the battery JST connector

ok, thanks a lot for info.

great soldering tutorial right in on pimooroni ,good luck