SNES Wincupl ATF15xx Repro cart

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mightydidz
Posts: 18
Joined: Wed Jan 24, 2018 12:04 pm

SNES Wincupl ATF15xx Repro cart

Post by mightydidz » Mon Jun 10, 2019 9:24 am

Hello everyone, I'm looking for some help with wincupl.

I want to build a repro cartridge for the snes and I want to use a cpld instead of 139 decoder and 257 mux.

I've already built custom cartridge for snes repro, even multigame cart, but this time I want to make it lighter and differently.

I want to built it using ATF15xx.
First revision would be only for a single game. Later I'll add the multigame feature
I want use the CPLD to control the ROM!CE, RAM!CE in both $20 and $21 mode.

I've just recently started learning Cupl language.
I've looked at two YouTube video, wich I found really interesting
https://youtu.be/IRthRE_wJQk
https://youtu.be/i-YzbfiNWl4

I'm looking for some help on the cupl equations.
So lets say I have a jumper on the cart for the mode selection named mode
low = $20, high = $21
In $20 mode, Rom is enabled whenever A15 is high and Romsel is low and Ram is enabled when A15 and Romsel is low and A20 and A21 are high
So in cupl:
!ROM/CE = MODE & !A15 & ROMSEL
!RAM/CE = MODE & A15 & ROMSEL & !A20 & !A21

In $21 mode, Rom is enabled whenever Romsel is low and Ram is enabled when Romsel is high and A22 is low and A13 and A14 are high
so in cupl:
!ROM/CE = !MODE & ROMSEL
!RAM/CE = !MODE & !ROMSEL $ A22 & !A13 & !A14

Am I on the right track so far?
Thanks for the help.

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