Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!apple!dlyons
From: dlyons@Apple.COM (David A. Lyons)
Newsgroups: comp.sys.apple
Subject: Re: 4k-Xmodem
Message-ID: <39112@apple.Apple.COM>
Date: 1 Mar 90 22:41:45 GMT
References: <300.infoapple.net@pro-generic> <2311@ultb.isc.rit.edu> <9159@wpi.wpi.edu> <3713@sage.cc.purdue.edu>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 35

In article <3713@sage.cc.purdue.edu> aj0@sage.cc.purdue.edu (Eric Mulholland) writes:
>[...]
>On the topic of communications, what is the perfered method for cdas
>wanting to use the serial port and keyboard?  I'd like to release a cda
>version of my communication program, but don't know how to communicate
>with the serial port or keyboard.  The current version is in Prodos 8
>because I'm not rich enough to afford all the gs reference books.  Now
>only if those books could come out in paperback.

Reading the keyboard is pretty easy--either do an EMStatus to see if the
Event Manager is active (use GetNextEvent if it is, and read the keyboard
at $E1C000 directly if not), or use GetIRQEnable and IntSource to turn
off keyboard interrupts while you're in your CDA (and then always read
the keyboard hardware directly).  There *is* a GS Technical Note available
that addresses that ("CDA Tips and Techniques", one of the fairly recent
ones).

Using the serial ports under GS/OS, and especially from a CDA, presents
some complicated questions.  How are you doing it now, under P8?  If you're
using the firmware, FWEntry will help a lot.  A future Technical Note will
go into great detail on serial-port-related issues under GS/OS.

Your basic choices are to use GS/OS drivers to do all or most of the
serial operations; to use the firmware; or to go directly to the hardware.
('course, there are various advantages and problems with all of these.)

Having the reference books is really helpful, too.
-- 
David A. Lyons, Apple Computer, Inc.      |   DAL Systems
Apple II Developer Technical Support      |   P.O. Box 875
America Online: Dave Lyons                |   Cupertino, CA 95015-0875
GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
Internet/BITNET:  dlyons@apple.com    UUCP:  ...!ames!apple!dlyons
   
My opinions are my own, not Apple's.