Re: CP/M on //e?

[dempson@actrix.gen.nz (David Empson)]

Doug Spence <ds_spenc@alcor.concordia.ca> wrote:

> Louis Schulman (louiss@gate.net) wrote:
> 
> : What you evidently have is a timing problem that occurs with certain
> : coprocessor cards (like the Z-80) and certain versions of the //e.  The
> : fact that you have a Revision A may be relevent, because this problem
> : does not occur for everyone.
> 
> Argh!  How was the timing changed between the ][+ and //e, and why?  
> (Oops, that looks rather technical. ;) )

Yes, it is.

There are some differences in the timing of DMA (direct memory access)
transfers : a card which uses DMA must set up the address a little
earlier on a IIe than on a ][.  Most Z80 cards make use of DMA, so this
is the area which will cause the most trouble.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand