[Coco] Static RAM in CoCo3?

[jdaggett at gate.net]

On 21 Jun 2006 at 16:06, Roger Merchberger wrote:

> >You have to configure the SRAM in 256Kx16 for a 512K block. That would
> >require 4 128Kx8 SRAMs.
> 
> Or one 256kx16. I've already found 'em for under $5.00. Alliance Semi's
> number for 'em is AS7C4098, and the datasheet is here:
> 
> http://www.ortodoxism.ro/datasheets/AllianceSemiconductor/mXvsvsu.pdf
> 
> The chip on the ReMem is 1024Kx16, IIRC. Replicate the hardware mods for
> the Disto 2M upgrade, and one could have a 2M CoCo in just a few chips. [[
> Or, at least that's what I was thinking... ]]

***************

You can use 16 bit wide srams as long as they have the abiolity to 
read and write to the upper and lower bytes independantly. While 
the GIME chip reads video data in word format (16 bits), the 6x09 
writes in  byte format. The GIME chip determines which bank, WE0 
and WE1, to write depending on state of the A0 line from the CPU. 


james