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Path: utzoo!linus!philabs!cmcl2!acf4!tsc2597
From: tsc2597@acf4.UUCP (Sam Chin)
Newsgroups: net.micro.pc
Subject: Re: Running IBM serial boards at 19.2KB
Message-ID: <1050023@acf4.UUCP>
Date: Mon, 22-Apr-85 23:10:00 EST
Article-I.D.: acf4.1050023
Posted: Mon Apr 22 23:10:00 1985
Date-Received: Fri, 26-Apr-85 01:47:47 EST
References: <535@cyb-eng.UUCP>
Organization: New York University
Lines: 14

<>
I don't know about 8250 UARTS, but with 8251 USARTS you have to worry about
the clock. If you use X16 mode and a 2 Mhz clock. The divisor which you have
to send to the counter (the 8251 has to be driven by an external clock) is
2.0 * 10E6/baud rate * 16 = 6.5
You unfortunately cannote send fractions to the counter and 6 or 7 don't
work. The solution for the 8251 is to use X1 mode in the counter but I don't
know how that would be done for the 8250. The point is that the clock does
matter. In the above example, if the clock was raised to 2.5 Mhz, you would
have a nice (almost) round 8.

                                              Sam Chin
                                              tsc2597.acf4@nyu
                                              allegra!cmcl2!acf4!tsc2597