Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!hplabs!hpda!hpcuhb!hpihoah!bruce
From: bruce@hpihoah.HP.COM (Bruce LaVigne)
Newsgroups: comp.os.minix
Subject: Re: AN HISTORIC MOMENT!
Message-ID: <4200004@hpihoah.HP.COM>
Date: 14 Jul 88 14:57:05 GMT
References: <841@ast.cs.vu.nl>
Organization: Hewlett Packard, Cupertino
Lines: 20

> It may be that the chip actually works at higher speeds, but this is outside
> the specification, at the very least.

It has been a while since I worked on that chip, but I did some stuff for a
terminal emulator company back in the XT days.  As I remember, the bytes you
actually stuff into the chip are divisors of an externally input clock.  With
the clock that IBM used, if you go above 9600 you start using non-integer
divisors.  What this means is that since you can really only use integer
numbers into the chip as a divisor, you don't get 19200 but something kindof
close.  If the other side can handle it, fine, but IBM doesn't support it.

-bruce

          Bruce LaVigne

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