Avenue 6 Pad

[smellyguineapig]

I know it's kind of pontless, but I want to make my own PC Engine 6 button pad circuit, before I start I wanted to check if anyone has done this before, could save me the trouble.

[NFG]

There's really nothing to it, it uses three of the same chips the regular controller has only one of.  I've at one time made up a diagram showing how it works, but I seem to have lost it, it's not where it should be.  The relevant data is there tho, with that page and a screwdriver you should be able to map out the guts of the pad in about 20 minutes.

[smellyguineapig]

I should have been more specific, the only thing that puzzles me is the 3 select and 3 enable pins, how they are handled with a 6 button pad.


The way I understand it, one 74hc157 takes the outputs of the first two 74hc157 ICs, one has the standard inputs, up/down/left/right/I/II/start while the other takes G/G/G/G/III/IV/V/VI (not particularly in that order).



So I'm guessing something else has to be done, otherwise the 74hc157 would end up taking the same outputs from the first two....


I hope I am making sense, this would be so much easier with a real 6 button pad, all I have is a third party pad that uses custom ICs, with the markings sanded off.

[NFG]

Yeah, you've got the situation right.  Where a normal pad has a '157 that switches UDLR and St/Sl/I/II (a two-stage process) the 6-button has a four stage process, using one '157 to switch between the other two.  If I had the diagram I'd give it to you.  Might have it in an old book, in fact...