Installing EGA or VGA in an AT&T PC6300
Bill Mayhew
wtm at uhura.neoucom.EDU
Thu Jun 14 07:05:33 AEST 1990
I have appended an article that appeared on this net a while back
that gives pretty complete details on the topic. I can't really
add anything myself.
I am using an STB EGA+ board in the 6300 where I am typing this
very article. The STB was (is??) one of the few EGA cards that can
operate at 25 KHz, which means that you don't have to junk your
original AT&T color monitor if you have one. If you are starting
with a monochrome system, you might as well get a Paradise VGA+/16
and a Sony 1304 monitor ... that happens to be my favorite
combination. The VGA+/16 can operate in either 8 or 16 bit slot,
as the VGA+/16's BIOS has auto sensing.
The bad part of switching to EGA or VGA on the 6300 is that many
lazy programmers do 16 bit writes to the I/O ports on the EGA
board. Becuase the PC6300 was introduced before the IBM AT, the
6300 has a low byte - high byte order sent to the I/O bus opposite
of the way IBM does it. That means that 16 bit writes on the 6300
usually wind up with crashed programs. D-R GEM Desktop is one of
the relatively few applications that work correctly out of the
box. There is a hardware solution to the mixed-up bytes, as is
mentioned in the article below.
==Bill==
Attachment follows:------------------------------------------------
Path: neoucom!spl1!laidbak!att!ihnp4!ihlpf!gpw
From: gpw at ihlpf.ATT.COM (Wilkin)
Newsgroups: att.sys.pc6300,comp.sys.att
Subject: 6300 upgrade options(286 and EGA)
Message-ID: <5457 at ihlpf.ATT.COM>
Date: 28 Jul 88 14:38:33 GMT
Reply-To: gpw at ihlpf.UUCP (Wilkin,G.P.)
Distribution: usa
Organization: AT&T Network Systems
Lines: 336
Xref: neoucom comp.sys.att:4195
==============================================================
Not the 6300 Newsletter George Wilkin
==============================================================
This month: Speed and Graphics!!!!
Subject: SOTA MOTHERCARD 5.0/5.0A James Butts
Subject: SOTA 286 ACCEL. CARDS David Gay
Subject: MAGNAVOX 873 James Butts
Subject: V30/QFRESH 6300 UPGRADE David Gay
Subject: EGA/VGA FIXES FOR 6300 David Gay
Subject: Pinout for Taxan 9 pin Bob Eberly / George Wilkin
to 25 pin AT&T cable
I was reading the AT&T Hotline BBS [1-201-769-5616] and found this info,
it is very useful. gpw
Please post the MultiSync cable pinout if you have a copy.
Date: 07-16-88 (23:47) Number: 1536
Subject: SOTA MOTHERCARD 5.0/5.0A From: JAMES BUTTS
After reading the West Coast newsletter (NEWS8801.arc) I picked up a
copy of Personal Computing (July, 1988). There is a complete review of
accelerator boards, & the Sota 5.0 is reviewed. It is compared to
several other boards plus a Compaq Portable (1) & Compaq 386/20 (5).
The review speaks very favorably to the Sota 5.0 & even suggests it is
able to run head-to-head with 386 boards. In the product chart,
following the article, the 5.0a is noted & listed as compatible with the
AT&T 6300. In overall value the Sota 5.0 is rated the highest of the
286 boards (Inboard 386/PC is top rated but NOT compatible with AT&T) at
8.2 on a scale of 1-10. I will put together a text file if others are
interested in this article. =-=-=- Jim -=-=-=
P.S. - Sota 408-245-3366 $895
Date: 07-17-88 (02:06) Number: 1539
Subject: SOTA 286 ACCEL. CARDS From: David Gay
=======================================================================
SOTA 286 Accelerators for AT&T PC6300 now available
=======================================================================
The SOTA (State Of The Art) Technology Inc. 80286 accelerator card for
the AT&T 6300 is now available. It is called the SOTA286i, and there are
10Mhz and 12.5Mhz versions. SOTA also makes an 80286 "computer on a
board" called the SOTA Mothercard 5.0A, which goes in an AT&T (that's
what the "A" stands for) and REALLY soups up a PC6300. I have never
actually seen one of these animals, but I have gathered a lot of info
from a guy called Bill Todd in San Jose who specializes in upgrading
AT&T 6300 systems. This guy HAS tested the above hardware in PC6300s and
posted the test results for downloading from his TODD PC3 BBS
1-408-263-9015 (1200 baud). I downloaded these results, which are quite
impressive, and uploaded them to this BBS. A BRIEF summary follows.
>>>>>>>Look for a file called SOTA286I.ARC for more info.<<<<<<<<<<<<
Pricing info:
SOTA286i 80286 accelerator with 16K SRAM cache, socket for your 8086,
and 2 foot cable to reach the 8086 socket on your motherboard:
10 Mhz 80286 - $495 SALE! $299 if you order before July 31!
12.5 Mhz 80286 - $595 SALE! $399 if you order before July 31!
SOTA Mothercard 5.0A with 1Meg of zero wait state on-board memory,
will supposedly run OS/2 out of the box!?!?
10 Mhz 80286 - $895 or $995 <- I have seen different prices
12.5 Mhz 80286 - $995 or $1095 <- from different sources here..
------------------------------------------------------------------------
PC TECH JOURNAL's ATPERF BENCHMARK RUN ON AT&T 6300 with HARDWARE:
PC/AT 339 AT&T 6300 SOTA286i SOTA5.0A SOTA5.0A
8Mhz V30/QFRESH 12.5Mhz 10Mhz 12.5Mhz
Avg instruction fetch 1.0 0.79 1.83 1.08 1.36
Avg Ram read time 1.0 0.78 8.65 1.09 1.37
Avg Ram write time 1.0 0.24 0.51 1.08 1.36
Avg ROM read time 1.0 0.16 0.15 1.09 1.37
Avg video write time 1.0 1.75 1.69 1.13 1.06
80286 CPU clock rate 1.0 0.66 1.52 1.21 1.52
-----------------------------------------------------------------------
Order from:
SOTA Technology Inc. or TODD PC3
657 N. Pastoria Ave. 1920 North Star Pl.
Sunnyvale, CA 94086 San Jose, CA 95131
408-245-3366 408-263-8925
------------------------------------------------------------------------
DISCLAIMER: I have not purchased these products, I am not making any
endorsements, I do not work for either SOTA or Bill Todd. Your mileage
may vary. I am passing this information along to the AT&T community
because the above mentioned concerns seem to be providing a viable
upgrade path for those of us with aging 6300s who want to get some more
bang out of the old box.
--David Gay-----
Date: 07-27-88 (23:53) Number: 1649
Subject: MAGNAVOX 873 From: James Butts
Jeff, With the AT&T cable the hookup is simple!!! (Use the part # in
my message! As for the horizontal prob., I would hope it was just a
factory prob. in set up. The are 2 master trim pots, 1 reads H.POS 22K
& the other reads H.POS 33K. The 22K refers to 22khz scan (Ithink) &
33K refers to 33Khz scan?! The 22K may have been set without checking
the 33K (as you know AT&T is 35Khz). Since I was operating on that
band, it had to be set properly. There is an external knob, right up
front, that allows you to get alot of horizontal adjustment with no
prob. I would like to guarantee no probs., but I don't know.
Good luck, =-=-=- Jim -=-=-=
Date: 07-26-88 (23:35) Number: 1633
Subject: MAGNAVOX 873 From: James Butts
I am now running a Magnavox 873 Multimode monitor with my native video
controler board! The dealer I bought it from did not know about the
AT&T adapter cord (Part #: 4613990288) so I followed the diagram for the
NEC (posted in files as MULTSYNC.ARC) & was successful in building my
own. ($12.00 in Radio Shack parts & 1 1/2 hrs. work). If your good with
an ohmmeter & soldering iron, go for it! (One point, it is 9 DB FEMALE
to 25 DB MALE for Magnavox!)
I had one prob., horizontal centering, but found the master trim pot. on
the mainboard on the right (facing monitor side). It could have just
been a poor setup at factory, not a real problem. (CAREFUL - you need
to be comfortable working on the INSIDES of a $500 monitor - HOT
CHASSIS! HIGH VOLTAGE!) It really wasn't any problem once I located
the pot. (no schematic).
The monitor is beautiful (made by JVC) & still operates in 640x400 AT&T
monochrome mode! I would recommend it 100% if I only knew about the
horizontal centering problem?!?!?!? One dealer told me it is out of
production already, but the dealer I ordered from (Computer Mail Order)
did not say this! Good luck, I hope this helps!! =-=-=- Jim -=-=-=
Date: 07-17-88 (00:50) Number: 1537
Subject: V30/QFRESH 6300 UPGRADE From: David Gay
=====================================================================
Replacing 8086 with 8Mhz NEC V30 and using QFRESH, by David Gay
=====================================================================
This is certainly the cheapest, easiest method of increasing the
performance of a 6300. Don't worry about a 10Mhz version, as PC Mag
suggested way back. The 8mHz V30 ($12) works like a charm, and increases
performance significantly. Just pull the 8086 from the motherboard, pop
in the V30, and you're running! In addition, if you use PC Mags QFRESH
utility (see below), you can get additional performance gains for FREE
by postponing the Dynamic RAM refresh.
PC Mag Labs Benchmarks 8086 V30 V30/QFRESH RATIO
128K NOP Loop: 4.56 4.61 4.34 1.05
Do-Nothing Loop: 6.26 5.22 4.61 1.36
Integer Add Loop: 5.21 3.95 3.57 1.46
Integer Multiply Loop: 5.77 2.91 2.53 2.28
String Sort and Move: 5.87 4.39 3.95 1.49
Prime Number Sieve: 8.24 6.04 5.88 1.40
8086 Instruction Mix: 18.24 13.41 11.64 1.57
Floating Point w/o 8087: 72.72 55.69 49.54 1.48
Conventional Memory Read: 3.57 1.98 1.75 2.04
Conventional Memory Write: 3.57 2.03 1.21 2.95
---cut below here and save as QFRESH.SCR-----------------------------
N QFRESH.COM
A 100
MOV AL,74
OUT 43,AL
MOV AL,FF
OUT 41,AL
MOV AL,02
OUT 41,AL
INT 20
<----------this is a blank line, erase this comment
R CX
E
W
Q
<----------this is a blank line, erase this comment
---cut above here and save as QFRESH.SCR----------------------------
At the DOS prompt, with DEBUG pathed, enter:
DEBUG < QFRESH.SCR
this creates QFRESH.COM, which you then run, or put in your AUTOEXEC.BAT
file. The low byte value of FF in line 5 and of the high byte value of
02 in line 7 may have to be changed for your own machine. See other
messages on this board for other people's values which work with a stock
8086, and also read the original PC Magazine article: Vol 7, No. 13,
July 1988, p. 331., which explains what is going on here.
-
Hope this helps some of you people out there. This board has helped me
a lot, so i thought I'd return the favor a bit.
---david----
Date: 07-17-88 (00:55) Number: 1538
Subject: EGA/VGA FIXES FOR 6300 From: David Gay
=====================================================================
Adding EGA/VGA board to a PC 6300, by David Gay
=====================================================================
If you call the AT&T Hotline up and ask about putting an EGA or VGA
board in a 6300, they will tell you you shouldn't do it, but will sell
you a $35 chip to disable your native video board anyway. There is only
one problem with this: the EGA/VGA card will only work with certain
software. The problem stems from the 6300's Olivetti-designed 16bit to
8bit "bus converter" board which allows the 16bit 8086 to talk with the
8bit cards which you put in the expansion slots.
When the 8086 sends out 16bits at a time, this converter chops it
up into two 8bit bytes and passes it along to the card. Trouble is,
when Olivetti designed the thing, they chose the wrong order to send
the bytes out, as compared with IBM's later designs. OOPS. For a lot
of text based programs and even some low-performance graphics programs,
this is not a problem, since they talk to the video card 8bits at a time.
But in the case of high-performance graphics programs like Generic CADD,
Microsoft Windows and Word, EGA Paint, etc., your expensive new EGA card
just will not work. But, hold on, there is a solution! Of course, AT&T
did not provide the solution, but thank God for the free enterprise system,
and for hardware hackers out in Silicon Valley.
A hardware fix for the 6300 bus problem has been developed by W. Allen
of Cupertino, CA. The 6300 BUSS CORRECTION KIT contains hardware that
disables the resident video board (so you don't need to give AT&T the $35
mentioned above) AND corrects the way the In/Out words are written to the
bus, thereby allowing EGA/VGA cards to work correctly on the AT&T 6300.
All kits come complete with the required hardware and good installation
instructions. I ordered one of these kits from W. Allen, received it in a
week, and put it into my 6300 in 15 minutes. The Paradise EGA / NEC Multisync
combo that would not run GENERIC CADD or MICROSOFT WINDOWS before installation
now gave me perfect performance. I highly recommend this fix, and congratulate
W. Allen for providing a solution to a problem which the technical might of
AT&T has chosen to ignore, rather than to solve.
To order your Buss Correction Kit, send $45 check or money order to:
W. ALLEN ASSOCIATES
10120 Lockwood Drive
Cupertino, CA 95014
(408) 257-9739
Postage and Handling is included. Send money order for faster processing.
A CAVEAT, AND ANOTHER SOLUTION: In its infinite wisdom, Olivetti
designed the 8bit expansion bus to operate at 4Mhz!!!! That is a little
bit slower than the original IBM PC. Consequently, EGA ROM BIOS video
operations, such as text scrolling are INCREDIBLY SLOW when you hook up
a EGA card in the AT&T. Fortunately, there is a solution. A program
called RAM4EGA copies the EGA ROM BIOS into Ram on the motherboard and
makes it resident. Video writes which use the bios are speeded up to
about the speed of the original AT&T display adapter on my system. The
information on this useful utility follows:
RAM4EGA Version 1.10
(C) 1988 - DLF Solutions!
This Device Driver will relocate EGA ROM at Address C000:0000 to RAM,
and fix up the vector table to point to the "Shadow RAM". This will be
of benefit to 16 and 32 bit machines (80286/80386) that are slowed by 8
bit access to the EGA Video Adapter Card. Since this Driver searches
the low memory vector table for references to the EGA ROM BIOS Segment
it MUST be the first Device entered in your CONFIG.SYS file
(Device=RAM4EGA.SYS). If EGA ROM BIOS is not found at Address C000:0000
it will do nothing, otherwise it will dramatically speed up Video BIOS
Routines. As always, use this at your own risk, however, I would be
interested in hearing about any problems. Douglas L. Fraleigh 1405
Sadlers Wells Dr. Herndon, VA 22070
Hopefully, this utility has been uploaded to the BBS where you read or
download this file. It should be a file called RAM4EGA1.ARC. Good Luck
upgrading your 6300!!!
---I hope this file helps some of you folks out there----
---David---
Subject: Pinout for Taxan 9 pin Bob Eberly / George Wilkin
to 25 pin AT&T cable
How to make a cable to connect the 318 to the TAXAN or STB Card.
The connections for a 318 to these cards should follow this example which
is for a TAXAN 557 Gold Card. (The Paradise Card will NOT work with the
318 monitor.
The pinouts to connect the AT&T 318 monitor with the 25 pin connector to
a Taxan Gold Card (9 pin) are as follows:
25 9 Lead
PIN PIN Designation
1 8 H. Sync
2 1 SG
3 9 V. Sync
4 3 Red
5 4 Green
6 5 Blue
7 6 Intensity
8 7 NC
9 - NC
10 - NC
11 - NC
12 - NC
13 - Degauss
14 2 SG
15 2 SG
16 2 SG
17 2 SG
18 2 SG
19 2 SG
20 - NC
21 - NC
22 - NC
23 - NC
24 - NC
25 - NC
SG = Signal Ground
NC = No Connection
NOTE: If you use paired cable leads connect one lead as the lead
designation and the other as the SG. This provides a shielding effect
and helps eliminate any video interference. Bob Eberly
Most multifrequency monitors can handle AT&T's 400 line, 25 KHz video signal
with plenty to spare. In particular, a Magnavox Multimode with a cable
(from Magnavox) for the AT&T indigenous video card, works fine.
--
George Wilkin AT&T Network Systems,(IH MAIN BL)
2000 N. Naperville Rd. Rm IH4A157
Naperville, IL. 60566-7033
att!ihlpf!gpw work ph# (312) 979-4317
--
Bill Mayhew Northeastern Ohio Universities College of Medicine
Rootstown, OH 44272-9995 USA 216-325-2511
wtm at uhura.neoucom.edu ....!uunet!aablue!neoucom!wtm
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