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

Johnny Billquist bqt at update.uu.se
Thu Mar 19 11:13:38 CDT 2015


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...

	Johnny



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