Re: FLASH ROM on VIC-20?

Hi Jim,

On 18.11.2012 06:14, Jim Brain wrote:
> If someone has a link or information on a design, I'd be most appreciative.

I once added internal Flash ROM into the VIC-20 with my universal 6502 
RAM/ROM expansion. It's pretty straight forward and you can have a look at 
the logic equations of the GAL it uses (www.x1541.de). But the equations 
for the Finaly Expansion CPLD will be more suitable for what you want to do.

Some thoughts should be spent on proper timing on the Flashs /CE /OE and 
/WE lines, this could be a little bit tricky. Because of the extra /OE line 
it is different to normal SRAM.

A simple method to connect two write-only banking registers in TTL to the 
C64 (should work on VIC-20 the same) can be seen in my NeoRAM cartridge.

An implementation to write Flash on a cartridge with TTL only would be the 
Easyflash 1 cartridge on the C64. more on skoe.de/easyflash

Nicolas

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