On 2012-09-12, at 20:24, Gerrit Heitsch wrote: > On 09/12/2012 08:14 PM, silverdr@wfmh.org.pl wrote: >> >> And then using the second half for colour RAM replacment will be as easy as ORing it with _CS for 4114, routing 4114's _CS to SRAMs A16 and ORing R/_W? > > No, the color RAM needs to be replaced seperatly due to the way it's hooked up the VIC (D8 - D11). Argh.. seems I got too happily excited and wrote without checking the schematics... > That means it's read in parallel with the other RAM. Yeah - that makes sense :-( > You can either find another 2114 or LC3514A No, as before, it is not about finding 2114s or equiv but about replacing its function with something easily available for cheap. > (still easy enough to get) or use a 6116 (see C128 schematics for the general idea) or any other available SRAM that's at least 4 Bit wide and 1K deep. Just tie all unused address lines to GND and the unused data lines (D4 to D7) to +5V using resistors (they used 3.3KOhm in the C128). I know - that's the "brute force" approach. While I woudn't feel so bad about having most of the other half of a 621024 being unused (the first half is put to a very good use), I don't seem to like very much the idea of putting e. g. additional 32kx8 (the smallest I have easily available) in place of 1kx4.. Not only due to the RAM waste but also footprint. Still I guess there aren't many options available these days the 32kx8 is still less that half the price of a 4114 on eBay. -- SD! Message was sent through the cbm-hackers mailing listReceived on 2012-09-12 19:01:08
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