Path: utzoo!attcan!uunet!snorkelwacker!bloom-beacon!bu.edu!m2c!wpi!profesor
From: profesor@wpi.wpi.edu (Matthew E Cross)
Newsgroups: comp.sys.cbm
Subject: Re: Serial Communications faster than 2400 baud on a 128
Message-ID: <10201@wpi.wpi.edu>
Date: 25 Mar 90 23:22:57 GMT
References: <7113@ucdavis.ucdavis.edu> <3064@uwm.edu>
Reply-To: profesor@wpi.wpi.edu (Matthew E Cross)
Distribution: comp
Organization: Worcester Polytechnic Institute, Worcester ,MA
Lines: 16

In article <3064@uwm.edu> jgreco@archimedes.math.uwm.edu (Joe Greco) writes:
>You neglect the fact that sending to a printer is a one-sided operation - 
>a 64 can RECEIVE fine and a 64 can TRANSMIT fine at 9600 but has some trouble
>doing both at once.

I read, at one point, that the 64's serial had no UART chip, that it was 
implemented in software, and that was why it could not handle speeds above
1200 baud, which may explain why it can handle 9600 one-way.  The designers
of the 64 probably figured that there would never exist a peripheral for the
64 that would have to do more than 1200-2400 baud, and therefore would be
cheaper to implement in software than add a UART chip.  My question is,
would it be possible to add a UART chip to the 64's bus through the cartridge
(for lack of a better name) port, and write a driver for it and change the 
kernal pointer to from the old serial routine to the new serial routine,
so as to make high-speed communications more reliable (I don't think it would
require much hardware...)