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cknave / c64-pico-ram-interface

Let your Raspberry Pi Pico pretend to be a Commodore 64 ROM cartridge
BSD 3-Clause "New" or "Revised" License
217 stars 16 forks source link

wire a14 a15 instead of romh,roml? #3

Closed fanoush closed 2 years ago

fanoush commented 2 years ago

I was thinking roml,romh are some simple logic helpers to tell that address ranges are 8000-9f, a000-bf and e000-ff in single bits, if pico could match all address lines to determine those adress ranges it may not need those romh/roml signal inputs and match 8,9,a,b,e,f directly? then by having all 16 address bits it could also match other address ranges to emulate other features like ram expansion? or even emulate vic/sid to provide better audio/video?

EDIT: the assumption here is that you are limited on number of total GPIOs so you can't have both.

And BTW there is another generic RP2040 board available on aliexpress - the WeAct RP204 board https://www.aliexpress.com/item/1005003708090298.html which also has GPIOs 24 and 29 available (and extra button on 23) https://forums.raspberrypi.com/viewtopic.php?p=1955110#p1955110

fanoush commented 2 years ago

already discussed in #1 so closing