Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!noc.near.net!howland.reston.ans.net!agate!apple!goofy.apple.com!mumbo.apple.com!gallant.apple.com!alanmims1.apple.comalanmims!user
From: alan@apple.com (Alan Mimms)
Subject: Re: 8749 microcontroller, need help
Sender: news@gallant.apple.com
Message-ID: <alan-200993094458@alanmims1.apple.comalanmims>
Date: Mon, 20 Sep 1993 17:44:58 GMT
References: <CDnpvs.536@watserv2.uwaterloo.ca>
Organization: Apple Computer, Inc.
Followup-To: comp.robotics,sci.electronics
Lines: 53

In article <CDnpvs.536@watserv2.uwaterloo.ca>,
nowinski@sciborg.uwaterloo.ca (Andrew Nowinski) wrote:

> 
> I am just learning to program the 8749 microprocessor. 
> 
> I have a 8749 microcontroller, I would like to use Port 1 as
> a input/output port for a matrix keyboard, I would like to use
> four lines of Port 1 as the output and four lines as the input. 
> (The keyboard has 16 keys)
> 
> I would like to write a program that can identify each number
> (0..9) on the keyboard, and light 8 LEDs. So if I pressed the
> number 7 on the keyboard. The 7th LED will light up. I am also
> planning on connecting the 8 LEDs to pins 12...19. 
> 
> I have no idea on how to write the program to the 8749.
> That's why I posted this question. I know I do not have to use a
> microprocessor to do the above, but I would like to do it anyway,
> it will help me learn more about programming the microprocessor. 
> 
> I would really appreciate if someone showed me how to write a
> program that will do the above.
> 
> Thanks.
> 
> --
> Jack Nowinski
> E-Mail: nowinski@sciborg.uwaterloo.ca

If you call the nice folks at Intel, they will give you a number in Arizona
someplace (as I recall) that is their technical support center.  They have
a group that will send you up to three (as I recall) of their technical
notes for free via the mail.  You can ask for the one that talks about
driving a multiplexed keyboard via an 8048 (8749 is a higher capacity EPROM
version of the 8048 family).  It will tell you everything you need to know.
 Also try the Intel FAXBack service at 1-800-628-2283.  This is a way to
have tech info sent to your FAX machine (which IT calls back).  It's pretty
cool and there's lotsa info, including the phone number I mentioned above
for tech notes.  There is also a BBS where you can download sample code and
(maybe) ask for technical info.  The number for this is 1-916-356-3605.  It
supports up to v.42bis so you can use a fast or a slow modem.

If you REALLY get stuck, I might be able to help you.  Good luck.

-- 

Alan Mimms (alan@apple.com, ...!apple!alan)   | My opinions are generally
Velociraptor Herder                           | pretty worthless, but
Apple Computer                                | they *are* my own...
Art without engineering is dreaming.  Engineering without art is
calculating.
	-- Steven K. Roberts in "Computing Across America"
