Re: ROMs replacement for narrow board

From: silverdr_at_wfmh.org.pl Date: Sat, 24 Nov 2012 14:40:24 +0100 Message-Id: <F6282137-B3A7-4D9D-AB30-D153D5FBF7B7@wfmh.org.pl>

On 2012-11-24, at 13:09, silverdr@wfmh.org.pl wrote:

>> Anyway I try, I need extra logic that I can't build by what the 74LS00 and 74LS08/11 supply.
> 
> Yup - same here. I am now trying with swapped parts:
> 
> http://dl.dropbox.com/u/58002657/cbm/c64/epromel_memmap0.png

With limited success as well.

http://dl.dropbox.com/u/58002657/cbm/c64/rom_adapter_narrow1.png

A12 is handled the old way, A 14 is simple: goes LO whenever _CHAROM or _BASIC (A14B) goes low - one '08 gate. But A13 doesn't work. It goes LO whenever _BASIC (A14B) goes LO. So far so good but then it has to be switched via jumper when and /only/ when KERNAL (A14) is HI..

-- 
SD!
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