Schematic of a GM ALDL -> PC converter

[Michael F. Sargent]

Why bother?

Serial I/O is designed to be able to handle at least a 5% error in clock rates 
between sender and receiver. Using 8228 instead of 8192 is less than 0.5% 
error.

	Mike

----------
From: 	owner-diy_efi at coulomb.eng.ohio-state.edu on behalf of John Faubion
Sent: 	Wednesday, November 27, 1996 17:01 PM
To: 	diy_efi at coulomb.eng.ohio-state.edu
Subject: 	Re: Schematic of a GM ALDL -> PC converter

>  You can't program a PC UART to 8192 baud, but 
>you can program it to 8228 using a divisor of 14, which is close enough.  

Actually why not change the XTAL to a 3.2768Mhz and use a divisor of 25?
With the UART's internal divisor of 16 and a programmable divisor of 25
would get 8192. Plus this is a standard crystal which costs about a dollar.
Dual port serial cards for the PC are around seven dollars now. Looks like
a cheap way to talk to it. Or I guess someone with a bit more EE skills
could probably whip up a circuit for it using that crystal, a UART, a
couple IC's and a few discretes to connect to a parallel port. Anyone with
the know how for this willing to take a shot. I'm willing to build it.

John Faubion
jfaubion at beaches.net