Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!mattd
From: mattd@Apple.COM (Matt Deatherage)
Newsgroups: comp.sys.apple2
Subject: Re: firmware/DRivers
Message-ID: <53073@apple.Apple.COM>
Date: 19 May 91 17:59:09 GMT
References: <9105171740.AA09361@ensu.ucalgary.ca>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 34

In article <9105171740.AA09361@ensu.ucalgary.ca> hockley@ENSU.UCALGARY.CA (Dallas C. Hockley) writes:
>help!  I am trying to determine whether output from a GS/OS device driver call
>is routed through the serial port firmware or not.  If a sequence of charcters
>which can be interpreted as a control sequence for the firmware is to be
>transmitted, how can the control  be embedded or otherwise stopped from
>executing routines in the communication hardware?
> 

Well, this isn't as easy as I had thought.

The trick to knowing that you can send firmware commands through a GS/OS
driver is to see if the driver is "generated" - if it's a default driver
GS/OS creates to interface with the firmware.  If it's a generated driver
for any character or block device, all I/O is done by GS/OS through the
normal Apple II firmware on the peripheral card/port.

The problem is that the reference material doesn't seem to have any
information on how to do this.  I had thought you could see if a device was
generated by looking at bit 14 of the device characteristics word (returned
from DInfo).  However, the A-W GS/OS Reference says that bit 14 is for
"linked" devices (one of several partitions) and that bit 13 is reserved.
My memory says that bit 13 is for linked devices.

I don't have a final GS/OS Device Driver Reference here at home and I'm in
ProDOS 8 (where's that GS/OS version of ProTERM, anyway?) so I can't use the
Exerciser DA to check it out.  But I'll bet the A-W book is wrong.

-- 
============================================================================
Matt Deatherage, Developer Technical  | The opinions expressed herein are
Support, Apple Computer, Inc.         | not those of Apple Computer, and
Personal mail only, please.  Thanks.  | shame on you for thinking otherwise.
^^^^^^^^ Technical questions are not personal. Please post them instead.
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