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From: kamath@reed.UUCP (Sean Kamath)
Newsgroups: net.micro.apple
Subject: Re: Apple 2E/enhanced monitor rom
Message-ID: <3794@reed.UUCP>
Date: Sun, 6-Jul-86 08:22:13 EDT
Article-I.D.: reed.3794
Posted: Sun Jul  6 08:22:13 1986
Date-Received: Mon, 7-Jul-86 02:25:49 EDT
References: <222@neoucom.UUCP>
Reply-To: kamath@reed.UUCP (Sean Kamath)
Organization: Reed College, Portland, Oregon
Lines: 59
Keywords: interrupt response time

In article <222@neoucom.UUCP> wtm@neoucom.UUCP (Bill Mayhew) writes:
>/////
>Hi,
>
>	I just got in an Apple 2E/enhanced computer that is
>replacing an older vanilla Apple 2E in an lab application that we
>are running.  The application uses an ADC driven by interrupts to
>look at a process every 100 cpu clocks.
>
>	Everything was fine when we used regular Apple 2s and 2Es.
>Now our application bombs, as the monitor ROM (under DOS 3.3) seems
>to do something that regularly shuts off interrupts for 250-300 uS.
>
Hmmmm.  Strange.  The new roms are actually much better about letting
interrupt through.  The old roms would turn off interrupts for too long
in 80 column mode, thereby loosing characters at 1200 baud or above.  I
wonder if it's because the new interrupt routines push the a reg on the
stack.  No, I guess it stil shoves it in $45 as well.  Frankly, I'd
figure out where it bombs specifically.  The new roms are worth it.  I
think so, anyway.
>	I haven't received any tech info on what goodies the
>enhanced version has yet.  (I thot it was just a new CG ROM with
>the mouse characters, but they must've reworked the EF and/or CD
>ROMS too).
Like I said, the roms have better interrupt handling.  They also read
lower case, you can search for a address, value or character in memory,
as well as input characters.  The mini assembler is also there.  It's
just plain cooler :-)  The only thing they screwed up on royally was not
putting the new op-codes into the disassembler...:-(  But I got a fix
for that:-)
>
>	For my application, I don't give a hoot about the mouse
>support.  What I was wondering, does anybody know if I can
>de-enhance my computer by putting old ROMs in it?  Anybody happen
>to know if the EF and CD ROMs can be replaced with 2764s?  It would
>save us a lot of time to burn our own.

Yes, the roms are staight 2764's.  No problem.  Drop 'em right in.
Leave the 65c02, though.  And maybe the CharGen rom.
>
>	Thanx in advance to any respondants.
>
>Bill Mayhew
>Division of Basic medical Sciences
>N. E. Ohio Universities' College of Med.
>4209 SR 44
>Rootstown, OH  44272  USA     (216) 325-2511
>...!allegra!neoucom!wtm  (or something like that?)


________________________________________________________________________________

Sean Kamath

UUCP {ihnp4,decvax,ucbcad,hplabs}!tektronix!reed!kamath

US Snail:  Box 395 Reed College,
           Portland, OR  97202
           (503) 239-7458