NetNews Usenet Archive 1992 #19/NN_1992_19.iso/spool/comp/sys/m68k/1066

Text File | 1992-08-27 | 1.4 KB | 36 lines

Newsgroups: comp.sys.m68k
Path: sparky!uunet!ftpbox!mothost!white!sapphire.rtsg.mot.com!declrckd
From: [e-mail] (Dan J. Declerck)
Subject: Re: Minimum speed on processors
Message-ID: <[e-mail]>
Sender: [e-mail]
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Organization: Motorola Inc., Cellular Infrastructure Group
References: <7Hj-kv#@engin.umich.edu>
Date: Thu, 27 Aug 1992 15:34:24 GMT
Lines: 23

In article <7Hj-kv#@engin.umich.edu> [e-mail] (John P Wittkoski ) writes:
>
>For a 33MHz 68030, there is a minimum clock speed listed for it in
>the databooks. I think it's somewhere around 25Mhz for a 33MHz version, but I
>don't have my databook handy.
>
>My question is: why is there a minimum?
>One possibility I have heard is that the on-chip registers and/or cache
>are dynamic in nature, and since the chip is geared for 33MHz, it divides
>this down to whatever rate is needed for the refresh circuitry. Therefore,
>if you go below the minimum, the refresh rate slows to below the minimum
>needed for the refresh.
>
Just another datapoint: the 68332 can be clocked down to DC (0)

-Dan


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