4 MB memory unibus/qbus card (was Qbus split I&D?)

emanuel stiebler emu at e-bbes.com
Fri Mar 20 01:21:42 CDT 2015


On 2015-03-19 17:13, Johnny Billquist wrote:
> On 2015-03-19 17:02, Noel Chiappa wrote:
>>      > From: Mark Kahrs
>>
>>      > there are very nice SRAMs available: for example, the Cypress
>> CY62167
>>      > is a 2Mx8 1Mx16 RAM in 48 pin TSOP. So you'd need two ...
>>      > (n.b. there is a 4Mx8 but it's only in BGA, so fuggitaboutit).
>>
>> Actually, one 4Mx8 (assuming it's really only 8 bits wide) wouldn't be as
>> easy to work with as two 2Mx8; since most QBUS cycles are 16-bit word,
>> not
>> byte, you'd have to do two memory cycles for each QBUS cycle -> more
>> complexity.
>
> And for the 11/70, we're talking about 32-bit wide memory...

Just because nobody mentioned it so far, what about the cy7c1460?
1mx36, so you even get the parity if you like one.
Used them quite a lot, are nice chips, and speedy too.



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