larryw@dasys1.UUCP (Winston Lawrence) (02/13/88)
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Using the Atari XEP80 - Winston Lawrence
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The XEP80 card has finally made the transition from vaporware to
hardware this is a review of my experiences with the adapter box in
response to several queries that have been posted here. The XEP80
gives all 8-bit Atari systems a true 80 column by 25 row visible
screen. I say visible because the device internally can handle rows
that are 255 characters wide, with an 80 character display window.
.
The unit, about the same dimensions as a Hayes smartmodem, connects
to joystick port one or two and to a monochrome monitor. All connecting
cables and a power supply are included with the unit. Forget about
using a color tv or color monitor as a display device. The display is
legible on a black and white tv it is just not very good quality. I
tried the unit on a Panasonic color tv (with seperate video input ), a
sony black and white tv, a black and white Panasonic cctv monitor (my
normal display device for several years - up until a few weeks ago),
and on a Magnavox BMC-80 monochrome (amber) monitor. The normal (40)
column display fills the screen on both the Sony black and White TV
and the Panasonic (cctv) monitor. The BMC-80 displays an amber box in
the center of the screen with almost two inches of black border on all
sides with the normal Atari display.
.
Okay As I said before, scratch the color output, the display was
unreadable, which was as I expected. The Sony black and white TV and
the CCTV monitor both gave 80-column images (sort of) with the CCTV
picture being a little sharper. I say sort of because I seemed to be
missing around the first 10 characters or so of every line.
.
SLOW BURN - after all I paid for an 80 column display not 70 columns
with an invisible 10 character window right.
.
CALM DOWN - on went the BMC. Fantastic. The screen FILLED up. No more
two inch black borders. I got sharp legible 80 characters all visible.
I had expected this to be the best display as even with the 80-column
emulators (KERMIT, VT100) the BMC-80 gave the sharpest images.
.
Okay so what was wrong with my other displays? Well, it seems that
some tvs (and even monitors apparently) have a problem with a thing
called overscan, wherein they do not display the first few scan lines.
A normal 40 column Antic display takes this into consideration by not
using the first few scan lines, so my 'old' displays never saw
anything wrong.
.
Guess what. The XEP80 writes to each and every scan line, in its
entirety so if your tv/monitor doesn't display them, you won't see
80 columns either. If you are going to buy an XEP80, make sure that
you have a good monochrome monitor - NOT a TV.
.
The XEP80 comes with all the software needed to get you 80 columns,
and continuing the 8-bit tradition (thank you VERY much Atari)
SOURCE CODE for the XEP80 driver/handler and several useful BASIC programs
that demonstrate windowing, blinking characters, graphics e.t.c.
VERY NICE.
.
The software acid tests
=======================
Most sophisticated 8-bit software fails with the XEP80 as will most
(if not all copy-protected software). The XEP80 relies on its handler
being present in order to drive the hardware. Most copy protected
software comes on a disk with its own DOS and will either not allow an
'outside autorun type' handler to be loaded, or will wipe out said
handler because it uses ram based on its (the software applications)
view of memory and will wipe out the XEP80 handler even if it could
be loaded. Software that wrings every byte out of the normal 48K or so
of ram available to it, will ALSO fail because the XEP80 handler will
need a little under 2K of this for itself.
.
In general, any software that uses/modifies the display list or
writes directly to video ram or uses graphics modes other than zero
will fail. The XEP80 can be switched between 80-column and standard
display modes but you have to be careful about where you load the
handler so that it is not overwritten by graphics (mode) changes.
The XEP80 only intercepts calls to the E: S: and P: handlers (which it
replaces) if they use the handlers (via CIO and the IOCB calls). Most
'sophisticated' 8-bit software uses the display list and/or video ram
to provide good visual images and so fail.
.
Instead of just saying tough we blew it, the XEP80 documentation refers
to these display list calls as 'illegal calls' a minor but annoying
point as display list programming is one of the things that made the
8-bit Ataris the powerful (for the price) graphics machines they are.
.
BASIC works (just don't position the cursor into the non-scrolling 25th
row). All the DOS versions that I tried worked (MYDOS, DOS 2.0, OS/A+).
The assembler editor cartridge worked. MAC65 worked (an older disk
version - I don't have the cartridge version of MAC/65). My ACTION
cartridge failed, but then again my ACTION cartridge doesn't always load
properly anyway (I think I have a bad EPROM or something).
Deep Blue 'C' sort of works, after doing *any* compilation the system
'locks up' I think because it is overwriting the ram where the
XEP80-handler lives. The same thing happened with the 'cc8' compiler
posted on Usenet a while back. The actual 'C' programs work just fine
providing they do not 'violate' the display limitations mentioned before,
and the 'C-linker' works in 80-columns without locking up the system.
All of this was tried with an 800 and 800Xl with and without an ATR8000
expansion unit attached.
.
What else fails? Every comm program that I have failed. AMODEM,
BBS EXPRESS, CHAMELEON, KERMIT-65, JTERM. I did not try the TELINK
cartridge but then who would care if it worked anyway (no file capture
or transfer capabilities in TELINK at all). Every word processor that
I have fails; The Atari Word Processor (real-old predecessor to the
Atariwriter); text-wizard; letter-perfect; Atariwriter; Word Magic;
MEDIT; speedscript; all failed. I do have a REAL old BASIC MINI-WORD
processor (a pd program) but like TELINK its a kludge, very bad so who
cares if it works anyway. GAMES? a couple of text only adventure
games worked, but were formatted for 40-columns anyway. Otherwise
if they use Player-Missile-Graphics, Display list Modifications,
direct screen writes (all the standard stuff that gives our 8-bit
programs some flash) are all going to fail in 80 Columns.
.
I should qualify the term fail here. You DO NOT lose your normal Atari
screen capabilities. Fail means that you see nothing at best, or the
system locks up when you have the XEP80 loaded. I have a Y switch that
lets me switch the ouput between the XEP80 cable and the normal Atari
output cable. By moving the switch I can get 80-column or the standard
display, on the one monitor. A real nice future hack would be to have
the switch go to two monitors and have them active simultaneously.
The XEP80 buffers its own screen ram so the hardware as far as I can
tell could let you have TWO different displays running concurrently. A
program running on one and a trace of the code on another screen.
(Bug65 does that now with the other 'screen' being a printer). The
XEP80 also gives you eight, yes eight printer handlers (P1:(P:)
through P8:) P1: is the printer port built into the XEP80 (yes built
into the XEP80). P2: e.t.c are whatever other printer ports your
hardware/dos can support. I have three now, One in the XEP80, one in
my 850 interface and one in my ATR8000.
Unfortunately I only have one printer.
.
Lest this sound too negative at this point. I DO LIKE THE XEP80.
I bought it for telecommunications; program development; and word
processing. I am writing a comm program in 'C' to use the XEP80.
I hear that Atariwriter-80 is out (although I can't find anyone who
actually has it for sale yet) and that will handle my program
development/word processing needs when I get my hands on it. I am
sure that others out there are busily adapting/writing new stuff
to use this device.
.
One last benefit to the XEP80. Programs that can use the XEP80 also
run faster, in some cases 50-75% faster. A listing to the XEP80
screen screams by. Keep your finger CLOSE to CTRL-1 if you want to
actually read what you are displaying. Why? because the ANTIC
chip that used to handle the screen I/O is turned OFF by the XEP80
handler and the 6502 is not being constantly interrupted. A couple
of BASIC timing loops that I tested while printing to the screen in
a FOR-NEXT loop, ran almost 150% faster. I attribute this to the fact
that the BASIC interpreter was able to do its thing MUCH faster when
ANTIC wasn't stealing the 6502 CPU cycles.
.
I think this is enough for now - I hope that I have gotten my point
across. The XEP80 does exist and I like it. If you do some programming
and have a decent monitor you probably will too. If you are a heavy
Comm user, wait for the software to start flowing then buy the XEP80
-or- better yet take charge, write some software yourself and buy the
box now. If you DON'T have a decent monitor then you have to consider
whether the $200-$250.00 that it will cost you to upgrade your monitor,
buy the XEP80, and get a decent word-processor is cost effective to you.
Winston Lawrence. 02/12/88
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--
Winston Lawrence {allegra,philabs,cmcl2}!phri\
Big Electric Cat Public Unix {bellcore,cmcl2}!cucard!dasys1!larryw
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