From: Keith R. Williams
Subject: Re: 8051 clock
Date: Mon, 7 Oct 2002 23:16:26 -0400
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In article ,
> > >Steve,
> > >
> > >Read again, preferable the whole discussion and don't yell to me. If you
> > >still don't understand, come again. FYI, I build both 8751- and 8031
> > >using the original data books from Intel and Philips.
> > >
> > >pieter.
> > -----------------
> > I've built those up for YEARS with the SAME clock, or swapped any of that
> > type for any other with total impunity. What are YOU doing wrong?
> > -Steve
> > --
> > -Steve Walz email@example.com ftp://ftp.armory.com/pub/user/rstevew
> > Electronics Site!! 1000's of Files and Dirs!! With Schematics Galore!!
> > http://www.armory.com/~rstevew or http://www.armory.com/~rstevew/Public
> Well, I don't. But even if I do there's no reason to yell about it. FYI, I
> repeat the original question below:
> > Hello,
> > Well i have problem with 8051 clock,
> > i had connected the 2 small capacitors ~15nP but still no clock,
> > BUT , when i'm taking the 8051 out from the circuit and connecting
> > those caps with the vcc,GND i can see the clock as it should be.
> > my circuit is simple 8051,74373 and eeprom(at28c64), how can the
> > circuit cause me to loose the clock..?? (i check all the connections
> > the relevan to the clock)..
> > Please your advice,
> > Eitan Herman.
> Having so much experience, you will admit that you may run into
> unpredictable problems using a 8051 in a board that has not been designed
> for it, *unless* you pull the /EA pin, to inhibit the internal ROM making
> the 8051 behave like a 8031 as Spehro Pefhany added.
> So there never has been a point about the absence of a clock circuit in a
> 8051-family processor until *you* thought it was.
Actually, no. You wrote:
> Do you really have a 8051 or is it a 8031? A 8051 is a mask
> rom version and can only be used in a circuit that has been
> developed for it. Putting it in another circuit will give
> unpredictable results, including clock failure.
This is quite false and RSW called you on it.
Even though RSW is an ass, he's right here.