MiSTer FPGA Forum

I was having problems with my I/O board but I've now isolated the issue to the DE10-Nano itself.

I have no add-ons boards connected except for the SDRAM-XSD (v2.4, 128MB).

If I touch a screwdriver to GPIO17 (PIN_AG23), the MiSTer will reset. The other button pins (GPIO13 / 15, user / osd) do NOT activate when touched by a screwdriver.

I first discovered this issue when I connected an external button to the I/O board (P3 header) and simply connecting the wire caused the DE10-Nano to reset.

Can anybody confirm this issue or check if the internal pull-up is activated? If not, can I safely add a pull-up resistor (10k) between GPIO17 and GPIO29 (3.3v)? Would this solve the problem?

I've added the resistor and it worked ... until I put the MiSTer into my arcade cabinet so it only half-solved the problem.

Some folks have told it might be A/C signal coupled into the line? If so, is there anything else I can do to solve that?

EDIT: I tried a 4.7k resistor as well but it didn't help.

EDIT2: I've added a 0.1uf capacitor between GPIO17 and GND and it's working. I don't have any additional pull-up resistors connected. I still need to test long-term but does this make sense why it's working? The capacitor seems to be filtering out some noise so can I add additional capacitors values to also help make sure it's a clean a signal as possible?

Sorry, it's been a while since I looked at this and I'm in the process of moving so I can't check (everything is packed away).

The capacitor solution sounds familiar and I would give that a try to see if it solves the problem for you. Good luck!