[comp.sys.m68k] 68000 timing skew of !AS vs !xDS

techtom@crash.cts.com (Scott Swazey) (10/19/89)

In the Motorola User's Manual for MC68000 I cannot find a skew specification 
between the rising edges of !AS and !xDS (data strobes). The Timing diagram 
seems to indicate simultaneous transition. Is this correct???
Appreciate any hint
	 - thanks. 
-Scott

mslater@cup.portal.com (Michael Z Slater) (10/22/89)

They don't spec skew between AS and DS.  Althought they are shown to be
the same on the timing diagram, for true worst-case design you have to
assume that the delay from clock to AS is at the minimum, and clock to DS
is at the maximum (or vice versa).  Obviously, this is overly conservative,
but I see no way to pick a "reasonable" but safe value.

Anyone from Moto willing to comment?

Michael Slater, Microprocessor Report   mslater@cup.portal.com