[Coco] 512KB SRAM upgrade

jdaggett at gate.net jdaggett at gate.net
Wed Nov 22 15:58:20 EST 2006


Sylvain

I am in process of evaluating your circuit. Take no offense but as it stands now 
you may have some issues that need correcting. First off what is an issue is that 
the WE0 and WE1 lines should have inverters in each line and then fed to an two 
input "nor" gate. The output of that or gate then feeds the WE line of the SRAM. 
You want either WE0 or WE1 to activate the WE of the SRAM and not and the 
two together. In present configuration, I don't beleve the GIME chip will ever have 
both the WE0 and WE1 lines low at the same time. 

I am in process of evaluating the rest of the circuit and will get back with you on 
that analysis.

james.
On 22 Nov 2006 at 6:11, Sylvain Rousseau wrote:

> Hello,
> 
> I just finished the design for a 512KB sram upgrade for Coco3.  I have only one Coco3 so I'm afraid to try it in it until I got a spare Coco3 or a spare Gime chip.
> 
> If it works well, I want to make the design public.  I can give the design to Mary to put on the Coco Nutz E-zine.
> 
> If someone can help me to get a spare Coco3 or a spare Gime chip, please let me know.
> 
> P.S. I already have a spare MC68B09EP.
> 
> Regards,
> 
> Sylvain
> Quebec
> Canada
> 
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