IBM's EGA and VGA
Great Hierophant
First, can you use standard 64x1kbit modules if you find a
daughterboard with empty sockets?
Second, there are dipswitches on the EGA that allow you to set which
resources it uses and what type of monitor it connects to. Can anyone
give me the dip switch settings?
Third, can the EGA truly do 720x350 monochrome output in Mode 7 when
connected to a monochrome monitor or will it emulate it with Mode 1/3
640x350 monochrome?
Fourth, did anyone ever find a use for the two composite video ports on
the card? I believe a second daughterboard would have provided some
functionality, like CGA composite video support. Does such a beast
exist?
Also, IBM released a (full length?) 8-bit ISA VGA card called the PS/2
Display Adapter. It was a designed to upgrade a PS/2 Model 30 (maybe
the 25 also) to full VGA capability but naturally could work with the
PC, XT AT or XT/286. Has anyone ever seen or owned this card?
Apparently Scott Mueller had one and it contains 24KB of ROM (rather
than the more usual 32KB) and speads its addressing across
$C0000-$D0000 (while other VGA cards generally keep their ROM within
$C0000-$C7FFF.) Does it have any dipswitches or jumpers that need to
be set for it to work with certain options (like a monochrome instead
of a color monitor.)
Cheers
In article
<1143338521.4...@i40g2000cwc.googlegroups.com>,
great_hi...@hotmail.com says...
> I have four questions about the IBM Enhanced Graphics Adapter:
>
> First, can you use standard 64x1kbit modules if you find a
> daughterboard with empty sockets?
that depend on the card design.
>
> Second, there are dipswitches on the EGA that allow you to set which
> resources it uses and what type of monitor it connects to. Can anyone
> give me the dip switch settings?
sure if you give us the card make and model
>
> Third, can the EGA truly do 720x350 monochrome output in Mode 7 when
> connected to a monochrome monitor or
AFAIK, EGA has limited resolution of 640x350, the answer
IMHO would be no.
> will it emulate it with Mode 1/3
> 640x350 monochrome?
possibly but it won't be Hercules 720x480 Mono
resolution, you might end up with small screen in the
centre of the monitor etc...
>
> Fourth, did anyone ever find a use for the two composite video ports on
> the card? I believe a second daughterboard would have provided some
> functionality, like CGA composite video support. Does such a beast
> exist?
a daughter board add on is required to activate those 2
ports.
>
> Also, IBM released a (full length?) 8-bit ISA VGA card called the PS/2
> Display Adapter. It was a designed to upgrade a PS/2 Model 30 (maybe
> the 25 also) to full VGA capability but naturally could work with the
> PC, XT AT or XT/286. Has anyone ever seen or owned this card?
I personally never seen one, that doesn't mean they don't
exist.
> Apparently Scott Mueller had one and it contains 24KB of ROM (rather
> than the more usual 32KB) and speads its addressing across
> $C0000-$D0000 (while other VGA cards generally keep their ROM within
> $C0000-$C7FFF.) Does it have any dipswitches or jumpers that need to
> be set for it to work with certain options (like a monochrome instead
> of a color monitor.)
maybe is mother board dependent, early motherboards had a
switch to change between color and mono, that used to do
the trick for most video cards.
>
>
--
Cheers......
Cheers
--
Cheers......
Michael Karcher
> Third, can the EGA truly do 720x350 monochrome output in Mode 7 when
> connected to a monochrome monitor or will it emulate it with Mode 1/3
> 640x350 monochrome?
My reference, a german book called "Die Programmierung der
EGA/VGA-Grafikkarte" (programming of the EGA/VGA graphics card) clearly says
so. The EGA ROM even contains some replacement 9x14 characters for use with
monochrome monitors, for example an "m" using all eight columns relying on
the ninth column as space between the characters, as shown below: (to be
viewed with a fixed-with-font)
12345678 123456789
|*** ** | |*** *** |
|******* | |******** |
|** * ** | |** ** ** |
|** * ** | |** ** ** |
|** * ** | |** ** ** |
|** ** | |** ** ** |
typical EGA typical EGA
color (8x14) m monochrome (9x14) m
On the hardware side, it is the following: In the clocking mode register
(port 3c4, index 1) bit 0 determines 8 or 9 dots/character. This bit is
cleared (meaning nine) only in the default register settings for mode 7.
Also there is a bit in the mode control register of the attribute controller
(port 3c0, index 10h, bit 2) indicating whether the ninth row should be
background color (bit=0) or a copy of line 8 for characters in the range
192d to 223d (bit=1). Both of these bits exists since EGA. The VGA was the
first card to actually use these bits with the standard monitor.
Mode 7 of the EGA has following exact timings:
- Pixel clock: 16.257MHz
- pixels/character: 9
- Horizontal total: 98 characters
-> horiz freq: 18.43 kHz
- Vertical total: 368 lines
-> vert freq: 50.1 Hz
The standard MDA/Hercules text mode has exactly the same timings.
This opens some possibilites, of course. For example it should be possible
to run a 90 character mode with a horizontal total of 110 characters by
switching the card to 8 bits/pixel mode. Also it is surely possible to switch
to 43 lines of text.
Michael Karcher
thewises
>
> First, can you use standard 64x1kbit modules if you find a
> daughterboard with empty sockets?
AFAIK, only real IBM EGA cards required a daughterboard to have 128k of
video memory. Most(if not all) clone EGA cards came standard with 128k. Some
even had 256k, allowing for a second page in 640x350 mode.
> Second, there are dipswitches on the EGA that allow you to set which
> resources it uses and what type of monitor it connects to. Can anyone
> give me the dip switch settings?
>
> Third, can the EGA truly do 720x350 monochrome output in Mode 7 when
> connected to a monochrome monitor or will it emulate it with Mode 1/3
> 640x350 monochrome?
While you can use a monochrome monitor with EGA cards, I think that you're
limited to 640x350x2 graphics.
> Fourth, did anyone ever find a use for the two composite video ports on
> the card? I believe a second daughterboard would have provided some
> functionality, like CGA composite video support. Does such a beast
> exist?
Possibly. Some VGA cards had feature connectors which served a similar
function.
Didn't the EGA cards have a light-pen connector, also?
> Also, IBM released a (full length?) 8-bit ISA VGA card called the PS/2
> Display Adapter. It was a designed to upgrade a PS/2 Model 30 (maybe
> the 25 also) to full VGA capability but naturally could work with the
> PC, XT AT or XT/286. Has anyone ever seen or owned this card?
> Apparently Scott Mueller had one and it contains 24KB of ROM (rather
> than the more usual 32KB) and speads its addressing across
> $C0000-$D0000 (while other VGA cards generally keep their ROM within
> $C0000-$C7FFF.) Does it have any dipswitches or jumpers that need to
> be set for it to work with certain options (like a monochrome instead
> of a color monitor.)
I've never heard of this before. I do know that IBM dropped the EGA, MDA,
and CGA cards in 1987(along with the IBM 5150 and the XT). ATs made in 1987
or later had full-length VGA cards.
Great Hierophant
The dipswitch settings should allow you to use a 5153 color monitor,
which limits the EGA to 200-line modes (0/1, 2/3, 4/5, 6, D, E), a 5151
monitor, which limits the EGA to the 350-line monochrome modes (7, F)
and a 5154 monitor, which allows the use of every mode. They may also
need to be set to tell the adapter how much memory is installed in
kilobytes (64, 128, 192, 256).
Rick
The 8 IBM VGA bit card is mentioned in "Upgrading and Repairing PC's" as
IBM's option to upgrade older PC, XT, AT systems that originally came
with other (non VGA) options. But since IBM started putting the video
hardware on the motherboard with the PS/2 line at about the same time
this 8 bit VGA card was released it was probably a short lived product.
Never seen one either. But apparently they did exist.
Rick
RickE
> Can anyone provide me the dip switch settings for IBM's EGA card?
The meaning of the 4 DIP switches on the IBM EGA vary depending on what
other video adapters are installed in the system, so there are 5
different tables, I'll summarize them below. The amount of memory on
the IBM EGA card (64KB base, maximum of 256KB) is sensed, not
determined by switches or jumpers.
Table 1: EGA is the only video adapter in the system
SW1 SW2 SW3 SW4 Type of Display Attached and Initial Mode
Selection
OFF OFF ON OFF Monochrome (5151)
ON OFF OFF ON Color 40x25 (5153)
OFF OFF OFF ON Color 80x25 (5153)
ON ON ON OFF Enhanced Color - Normal Mode (5154)
OFF ON ON OFF Enhanced Color - Enhanced Mode (5154)
Table 2: EGA and Monochrome (MDPA) installed, EGA primary
SW1 SW2 SW3 SW4 EGA Display MDPA Display
ON OFF OFF ON Color 40x25 Monochrome
OFF OFF OFF ON Color 80x25 Monochrome
ON ON ON OFF 5154 - Normal Monochrome
OFF ON ON OFF 5154 - Enhanced Monochrome
Table 3: EGA and MDPA, MDPA primary
SW1 SW2 SW3 SW4 EGA Display MDPA Display
ON ON ON ON Color 40x25 Monochrome
OFF ON ON ON Color 80x25 Monochrome
ON OFF ON ON 5154 - Normal Monochrome
OFF OFF ON ON 5154-Enhanced Monochrome
Table 4: EGA and CGA, EGA primary
SW1 SW2 SW3 SW4 EGA Display CGA Display
ON OFF ON OFF Monochrome Color 40x25
OFF OFF ON OFF Monochrome Color 80x25
Table 5: EGA and CGA, CGA primary
SW1 SW2 SW3 SW4 EGA Display CGA Display
ON ON OFF ON Monochrome Color 40x25
OFF ON OFF ON Monochrome Color 80x25
You'll note that with two display adapters installed, one is always
acting as a monochrome adapter and the other as a color adapter, which
makes sense when you consider the memory address mapping. It also
means that the EGA/CGA combination is really a waste, if you are going
to use 2 display adapters it might as well be the EGA/MDPA combination
(or a VGA/MDPA combination).
As to the jumpers, P1 should jumper positions 2-3 when attaching a
monochrome (5151) or CGA (5153) display to the EGA, P1 should jumper
positions 1-2 when attaching an ECD (5154). P3 should jumper positions
1-2 to select I/O range 3xx, jumper positions 2-3 to select I/O range
2xx. Only the 3xx range is supported by BIOS. The P2 block is used
for a light pen input.
Rick Ekblaw
Cheers
In article <4426D0F2...@rcn.com>, rick...@rcn.com
says...
.
>
> The 8 IBM VGA bit card is mentioned in "Upgrading and Repairing PC's" as
> IBM's option to upgrade older PC, XT, AT systems that originally came
> with other (non VGA) options. But since IBM started putting the video
I have few 8bits VGA cards myself, have a look here
http://members.iinet.net.au/~moussa/v7-vega.jpg
and others EGA cards
http://members.iinet.net.au/~moussa/ega-grace.jpg
---
Cheers......
David L. Beem
> The 8[-bit] IBM VGA bit card is mentioned in "Upgrading and
> Repairing PC's" as IBM's option to upgrade older PC, XT, AT
> systems that originally came with other (non VGA) options. But
> since IBM started putting the video hardware on the
> motherboard with the PS/2 line at about the same time this 8
> bit VGA card was released it was probably a short lived
> product. Never seen one either. But apparently they did exist.
8086 (with base MCGA video) and older systems like the AT. It is in a ratio
almost like a microchannel card, able to fit in an XT or Model 30 case. I've
got two of them, and I think the IBM "Options" insert for a manual binder.
There is an apparent ability to add a VRAM daughtercard like the 8514/A
has. Off the top of my head I don't remember the base VRAM size, but I'm
sure it is on par with other PS/2 baseboard VGA. Let me see what I can pull
out & scan.
David
Da...@IBMMuseum.com
thewises
> 8086 (with base MCGA video) and older systems like the AT. It is in a
> ratio
> almost like a microchannel card, able to fit in an XT or Model 30 case.
> I've
> got two of them, and I think the IBM "Options" insert for a manual binder.
As I said previously, the PC and XT were discontinued in April, 1987(when
the PS/2s were launched). The AT, however, was produced for a few more
years. It was discontinued sometime around 1990. Prior to April, 1987, the
AT was avaliable with either MDA, CGA, or EGA video cards. Afterwards, the
AT was only avaliable with VGA. Like it's predecessors, IBM's VGA cards were
big full-length beasts.
It seems to me that IBM always had very inefficiently-designed hardware. For
example, most clone video cards had only half the number of chips that IBM
video cards had.
Great Hierophant
PS/2 Model 30-286, which eclipsed the AT with a 10MHz 80286 and better
RAM expansion. The same thing occured in 1987 when the PS/2 Model 30,
with its 8MHz 8086 and MCGA made the PC and XT obselete. After that,
even with ISA based computers there was no need for the PC line
anymore. (Also, although the XT and the AT have more slots than any
ISA based PS/2, they need to be filled with asych comm, printer,
diskette, fixed disk and video adapters to work as well as a PS/2.)
Also, IBM's VGA adapter was designed to work in 8-bit systems, but on
the PS/2 it was confined to systems with a 16-bit bus (either MCA or
ISA). The PS/2 Models 35 and 40 boast of an integrated 16-bit VGA
adapter, does this mean that the adapters in the PS/2 Models 25-286,
30-286, 50, 60, 70 and 80 are all 8-bit?
David L. Beem
> As I said previously, the PC and XT were discontinued in April, 1987
> (when the PS/2s were launched). The AT, however, was produced for
> a few more years. It was discontinued sometime around 1990. Prior to
> April, 1987, the AT was avaliable with either MDA, CGA, or EGA
> video cards. Afterwards, the AT was only avaliable with VGA.
AT, but not the discontinued PC or XT. The XT can run the card (a few months
back I did, because I had a VGA monitor & the card handy, but MDA & CGA
monitors more remote) fine, not so sure about the PC1 (limited ROM scanning
areas) & PC2. I think you are correct on the PC discontinued date, but there
was an IBM XT (not the 286 version) with 1986 BIOS (101-key keyboard, 720Kb
diskette support) as I recall.
> Like it's predecessors, IBM's VGA cards were big full-length beasts.
> It seems to me that IBM always had very inefficiently-designed
> hardware. For example, most clone video cards had only half the
> number of chips that IBM video cards had.
There was just one separate IBM VGA adapter made for the XT/AT bus.
While it is full-length, there isn't as much height as even other XT cards
(and almost half what an AT card can be). And IBM adapters & motherboards
before the PS/2 line were typically not VLSI, which would cover the time
period for all the other IBM video cards you mention, with the exception of
this solitary VGA adapter again.
David
Da...@IBMMuseum.com
thewises
> AT, but not the discontinued PC or XT. The XT can run the card (a few
> months
> back I did, because I had a VGA monitor & the card handy, but MDA & CGA
> monitors more remote) fine, not so sure about the PC1 (limited ROM
> scanning
> areas) & PC2. I think you are correct on the PC discontinued date, but
> there
> was an IBM XT (not the 286 version) with 1986 BIOS (101-key keyboard,
> 720Kb
> diskette support) as I recall.
The early IBM 5150s with the 16k-64k motherboards can't use EGA or VGA
cards(or hard disks) because the BIOS doesn't recognize adapter ROMs. The
5150s with the 64k-256k board can use them.
The XT was definitely dropped in 1987. It was replaced by the PS/2 25 and
30.
Great Hierophant
motherboard if you upgrade the BIOS ROM to one dated 10.27.82. IBM
even sold that chip as an upgrade.
thewises
> motherboard if you upgrade the BIOS ROM to one dated 10.27.82. IBM
> even sold that chip as an upgrade.
I suppose you could do that. I'd also like to point out that the earlier
BIOS could only recognize 544k of memory, even if you had 640k(the early
Compaq Portables had the same limitation).
David L. Beem
> like the 8514/A has. Off the top of my head I don't remember
> the base VRAM size, but I'm sure it is on par with other PS/2
www.IBMMuseum.com/IBMXTVGA.JPG
David
Da...@IBMMuseum.com
Great Hierophant
amount of RAM, 256KB, the modules would have to be 64x4bit devices. Is
that so?
Scott Mueller's diagram of the card is reasonably accurate.
David L. Beem
> I see that there seem to be 8 memory modules. To
> reach the proper amount of RAM, 256KB, the
> modules would have to be 64x4bit devices. Is that so?
> Scott Mueller's diagram of the card is reasonably accurate.
Which edition are you referencing?
David
Da...@IBMMuseum.com
Great Hierophant
IBMMuseum
>> Scott Mueller's diagram of the card is reasonably accurate.
> Which edition are you referencing?
"Upgrading and Repairing PCs", Que Corporation, ISBN 0-88022-856-3) he
has a bit of text (http://www.IBMMuseum.com/XTVGATXT.GIF) and an
outline (http://www.IBMMuseum.com/XTVGAIMG.GIF)...
David
Da...@IBMMuseum.com
IBMMuseum
in one:
http://www.IBMMuseum.com/Vid7VRAM.JPG. Compare the two outlines &
similarities. They look like they could use the same VRAM expansion
board!
Difference in bus width & maybe VRAM size (all 16 chips areHitachi
HM53461ZP-12). Many jumper settings, so I will need to find a manual
somewhere. Hidden from view in the picture is the name of the adapter:
"Video Seven V-RAM VGA (C) 1988".
David
D...@IBMMuseum.com
Great Hierophant
Is it possible to change the IRQ settings of the card?
Also, the main EGA board comes with 64KB of RAM. This must mean its
daughterboard has three banks of 64KB sockets. How do you tell the EGA
how much RAM it actually has?
Cheers
@e56g2000cwe.googlegroups.com>,
great_hi...@hotmail.com says...
> I thought of an two additional questions:
>
> Also, the main EGA board comes with 64KB of RAM. This must mean its
> daughterboard has three banks of 64KB sockets.
in the past we used to solder or piggyback a DIP ram on
the top of the other to extend the memory to 128K/256k,
now don't ruin yours!
> How do you tell the EGA how much RAM it actually has?
just like the VGA, it is auto detected by the card.
>
>
--
Cheers......