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Nicolas Welte's RAM/ROM board ROM structure...

misterdid

New Member
Joined
Jan 2, 2019
Messages
7
Location
Poughkeepsie, NY
Hi there,

I need help...

I recently bought on $bay a PET 2001-8 to add to my vintage computer collection.
After some refurbishment, it is working fine.

But in order to "improve" it, I built Nicolas Welte's RAM/ROM board from his gerbers...I get the 32K of RAM without issue.

Now, I am now trying to load the Flash ROM with Basic 4.0 (my PET 2001-8 had the "graphic" keyboard, no CRTC)...but I don't know how to build the correct OPTION/BASIC/... ROM structure and where to load them in the flash with my TL866II (for now I have only my C64/VIC-20 C2N tape...).

Anyone ?
 
Good find, that makes sense to map the base of rom to $8000 for simpler decoding, and then exclude video ram and io space with the GAL.
 
And each 32KB chunk can be a different version of BASIC, right? So if one used a 27C512 EPROM (64 KB), one could map two complete BASICs, say BASIC 2 and BASIC 4? And select the one to be used with the DIP switches?
 
Yes, Option ROMS, Basic, Editor and Kernal...

For now I have only created a ROM with Basic 4.0 (ROM switches 00) and PETESTER (ROM switches 01). Works great !
I will probably create a full "history" ROM 1.0 / 2.0 / 4.0 / Tester for my 2001-8 with this 128K EPROM.
The only issue is with the current 6502 socket. It is a little too shallow and the adapter is not super secured in it...I plan to replace it with a brand new turned pin socket later.
 
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