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From: news@macuni.mqcc.mq.oz (USENET News System)
Newsgroups: comp.sys.mac.programmer
Subject: Re: can the serial driver run at 38400 baud?
Summary: Yes and it's easy
Keywords: serial driver 38400
Message-ID: <775@macuni.mqcc.mq.oz>
Date: 16 Nov 90 00:51:11 GMT
References: <1990Nov10.021930.16649@morrow.stanford.edu> <11202@goofy.Apple.COM>
Reply-To: s8925188@mqcomp.mq.oz (Philip Craig)
Organization: Macquarie University
Lines: 28

>In article <1990Nov10.021930.16649@morrow.stanford.edu> GG.DAR@forsythe.stanford.edu (Aaron Reizes) writes:
>>I have a program that does serial communications.  I have gotten
>>requests to support speeds above 19.2kb.
>>
>>It looks like baud38400 should be 2 but I have not been able to get
				   ^^^ -- no it should be 1
From: s8925188@mqcomp.mqcc.mq.OZ (Philip Craig)
Path: mqcomp!s8925188

>>the driver to respond to 384kb.  I have tried 1, 2, and 3 as the
>>divisor.
>>
>Read IM-II chapter on the serial driver.  You need to set up a parameter
>block and make a control call to the output driver...
>
>IM II-254/255. csCode = 13, csParam = baudRate.

While Byron's method will work, I have found that a constant of 1 works just
fine for me. There is an entry in the Q&A stack that mentions this. It also
gives the arcane division formula for working out your own rates. Now the
interesting question is: why did Apple leave it out of the constants, and 
why is it still left out?
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