I see the pinout for famiclone controller at https://wiki.nesdev.com/w/index.php/Con ... ort_pinout. Is adding a DB9 port for controller 1 a matter of wiring those five wires to a male DB9 connector? I am assuming--perhaps incorrectly--that the five wires correspond to D0, OUT0, CLK, GND and 5V. How do I determine which wire corresponds to each function?
That blob seems to be like the controller IC, maybe it's possible to add the port by picking the tracks that go to it.
I really would like to hear the opinion of more experienced users, like Lidnariq and Krzysiobal.
We have a pinout for a UM6582 on our wiki, but that's a 16-pin part, and the footprint on your PCB only has 14 lands... but it looks like it might almost be the same with two extra pins at the top.
This implies that the chip-on-board there is a UM6582 - see also the turbo buttons - and you'll have to remove the chip-on-board in order to plug an external controller. After that, you can probably use the remaining UM6582 SOP footprint to attach the external controller.
Thanks for weighing in. There's a lot in your response for a beginner to unpack.
I'm interpreting your reply to mean that under one of the blobs is a UM6582 and that it needs to be removed. I'm not clear on what to do after that. I recognize that I may have to do a lot of research given my skill level. I may need a nudge to get me started. How would I determine how to connect the 9 pin famiclone port?
I suspect that pins 2-14 in the above link correspond to 13 of the pins on the empty square marked "UM6582" on your PCB. That's where you connect your famiclone controller. (What pins go where? I don't know, I've never personally seen a DE9 famiclone controller, so I don't know if there's one convention or multiple, or how to determine which you have. You said you already have one DE9 port for player 2; three of the pins should be shared between the two controller ports)
Hard thing second:
In order to use an external controller, you must disable the equivalent chip on your PCB. I suspect this is the black epoxy blob that Fisher circled next to. These epoxy blobs often come off with a bit of heat and force. A lighter and a screwdriver might be good enough.
Be careful: if you damage the other blob at all, you'll just have a piece of junk.
https://wiki.nesdev.com/w/index.php/Con ... ort_pinout
I have read people finding multiple different 9-pin famiclone pinouts, so do NOT assume that the one on the above page is correct for you!
* First blob is NES-on-Chip
* Second blob is PRG ROM, CHR ROM and mapper
* Third blob is joypad controller (which as lidnariq find out is UM6582)
What I would recommend is not to remove the controller blob but instead, cut its data-out track, add two diodes to make OR gate to connect external controller. This way you still can use the built-in joypad.
The DB9 plug has two GNDs and two +5Vs so you can modify it and route $4016.D0 and $4016.CLK to it
Code: Select all
+5V | 2.2k | D of UM6852----------------|<---+--------D of Nes-on-chop blob | D of external joypad #1----|<---+