LED blinking and C64's does not work when plug in the PadSwitcher

[unebonnevie]

Hi,

I just assembled one. Flashed the firmware to the ATMEGA88A successfully. Checked everything thrice. Plug in the adapter. The LED blinks for a couple seconds. My C64's keyboard does not work when the adapter is plugged in. Unplug it and my C64's keyboard works fine. Strange!

Thanks for any tips.

[Hojo-Norem]

The flashing on power on is normal. It's to indicate that the firmware is operating. If your C64 is powering on to the normal blue screen but the keyboard is unresponsive until you unplug the adapter, then that sounds like what happens if you plug a normal joystick into port 1 and hold up.

My initial suggestion would be to pull the AVR from it's socket and plug the adapter back into your C64. If the keyboard still misbehaves then you have a short circuit on the adapter. With the AVR still unplugged, check for continuity on the adapter's joystick port pins between each other and the SNES port pin closest to the LED.

If that checks out okay then it looks like you may have a faulty AVR.

If neither of these were of assistance then a few good photos of your build may help root out the cause.

[unebonnevie]

Thanks for the response. My AVR ATMEGA88A is a good chip. I got it from Digikey.com and it's programmed successfully, thus seeing the blinking LED. I had also made sure that the fuse bits have the DIV8 bit OFF, meaning that it runs at 8Mhz internally.
My C64's keyboard does not respond with the ATMEGA88A in or not, that is, when the adapter is plugged in.

The SNES connector I got from AliExpress unfortunately does not have the exact orientation to the pins on the board. So its pins are soldered right on the surfaces of the holes on the board, thus, the big blobs of solder.

I checked and checked every solder point. Everything looks fine. I guess I'll build another.

Attached are some photos.

[Hojo-Norem]

Odd. Soldering looks good... My only guess is that there was a defect in the PCB when it was made.

I see that you've mounted your SNES socket so it faces away rather than up. Nothing wrong with that. The reason that the holes for the socket are so much larger is so you can use the SNES sockets with the shorter, thicker, straight legs... Which no longer seems to be available from what I can see.

These grey sockets with the bent legs seem the the most common now.

The reason I bring this up is that I soldered the socket on my first prototype similar to how you have, only for it to tear the pads away from the PCB. It may be worth bending the pins straight before your second attempt. The two inner pins of the group of three aren't used, so they are good candidates to see if the pins will bend without snapping.

[unebonnevie]

Thanks for the response.

My only guess is that there was a defect in the PCB when it was made

I hope not, because I got the gerber files from your github :-) I'll make another one, since I have 4 PCBs left. Will let you know how that goes. Unfortunately, that SNES connector was my last one, pending on an order for more connectors. Maybe I can desolder it off the current board.