riscy
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Re: riscy status

To: riscy@sunsite.unc.edu
Subject: Re: riscy status
From: Drew Eckhardt <drew@kinglear.cs.Colorado.EDU>
Date: Mon, 15 Nov 1993 22:03:19 -0700
In-reply-to: Your message of "Mon, 15 Nov 1993 05:21:13 EST." <199311151020.AA05584@picton.cs.huji.ac.il>
    On a second though, adding a doughter card must be going to rise the
    cost and time to design significally, isn't it?

No.  The signals on the SC and PC chips (with the exception of interrupt
levels > the first one) are 100% compatable, so you can go with the 
standard 179 pin PGA on the main board.

4000PC, 4200PC, and 4400PC chips are plug compatable, change them, the
crystal, and setup for the serially loaded boot data which determines 
the clock divisor and access pattern for the memory interface.

For the MC/SC series chips or a surface mount 4200, you can go 
with a daughter card that routes the pins to the right place, just 
like AMD does with their 386 chips, HP did with the 9000/400's which 
could take either a 68040 or 68030 + 68882, etc.


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