Correct use of pogo Reset pad?

Anonymouse · February 16, 2021, 12:01am

I would like to have a ‘reset button’ using the pogo pad on the underside of the Xiao (near the SWDIO/SWCLK pads).

What should I include to achieve that?

Is there anything else needed other than a tactile switch pulling that pin to ground?

Can it be any ground (i.e. the pin between 3.3v and 5v), or does it have to be to the ground pad next to it?

Do I need any resistors or capacitors to protect that pad?

I tried looking at the schematics, but I could only find one reset pad (TP2), and I wasn’t sure if that was the reset pad on the top or the one on the underside of the board?

reivilo · February 16, 2021, 9:11am

Have a look at the schematics of the Seeeduino XIAO Expansion board to see how the reset button is implemented.

Anonymouse · February 16, 2021, 11:25am

K2 - tactile switch directly to ground.

[edit a few days later]

While digging thru the SAM D21 spec sheet for something else, I came across this:

[reference: page 1022 of SAM D21G Datasheet]

I don’t see any reset circuitry on the Xiao spec sheet, so it looks like I will need to add a resistor and cap to rev 2 of my PCB.