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From: rdt@houxk.UUCP (R.TRAUBEN)
Newsgroups: net.micro
Subject: what is 68851 vlsi mmu translation time?
Message-ID: <423@houxk.UUCP>
Date: Thu, 9-May-85 08:30:55 EDT
Article-I.D.: houxk.423
Posted: Thu May  9 08:30:55 1985
Date-Received: Sun, 12-May-85 11:22:40 EDT
Organization: ATT Information Systems, Holmdel, N.J.
Lines: 21

Hello:

Motorola claims 45 nanoseconds for 68851 translation time on the
paged mmu (vlsi version, not the ttl mini-board gate array version)!

Measured from what event (as a starting reference) to what event
(as an ending point)? 

Virtual address 	valid to Physical address 	 valid?
Virtual address Strobe  valid to Physical address 	 valid? 
Virtual address Strobe  valid to Physical address STROBE valid? 
Does the Translation end point include the time to do access rights checking?

Any help is appreciated. I'm confused on what 45 really means.
Thanks,

	> Richard

P.S. 	Address out times alone on 68xxx (*MOS) parts are in the vicinity
	of 30 nanoseconds!