[Coco] 256K RAM chips

[Gene Heskett]

On Thursday 25 December 2008, Roger Taylor wrote:
>At 08:50 PM 12/24/2008, you wrote:
>>N8WQ wrote:
>>>Can you guys tell me if I might be able to use these memory chips
>>>in a Color Computer 3 project? Any ideas?
>>>http://exwn8jef.googlepages.com/cocoprojects
>>
>>Yep I have a load of them off 486/Pentium motherboards, they are
>>32Kx8, static ram and at -15, you're not going to have any speed
>>issues....as they are 15ns, for comparison the 4164s in my upgraded
>>Dragon 32 are 200ns......
>>
>>Cheers.
>>
>>Phill.
>
>So you're saying the CoCo could use these chips as-is plus they
>retain their memory when the power is off?

No Roger.  'static' means they do not need the refresh pump that drams need.  
Also at 32x8, a wee bit of address decoding will need to be done, but only 
the high bit, this is solved in the coco2's by simply feeding the high 
address bit through an inverter so that one or the other chip is enabled, but 
not both.  I'm not sure howto do that, and where, in a coco3.


-- 
Cheers, Gene
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