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Questions tagged [vga]

For questions related to VGA signals, sources or receivers

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Understanding the Need for Positive Sync Polarities in Sony PVM Monitors

Understanding the Need for Positive Sync Polarities in Sony PVM Monitors Note: This post has been edited several times during its lifetime, and some questions may have already been answered. I'm in ...
Tai Alt's user avatar
  • 73
14 votes
3 answers
3k views

Why does PC video memory base address change depending on video mode?

It is rather well-known that, with VGA-compatible PC video adapters, in black-and-white text modes video memory is available at linear address 0xB0000, in colour text mode at address 0xB8000, while in ...
user3840170's user avatar
  • 23.1k
7 votes
2 answers
571 views

Were VGA palette's HSV math properties used in practice?

In "Why were those colors chosen to be the default palette for 256-color VGA?", we've established that 216 of its colors represent a 24x3x3 truncated HSV color space. This results in an ...
Therac's user avatar
  • 753
37 votes
4 answers
8k views

Why were those colors chosen to be the default palette for 256-color VGA?

Although subjective, I believe I'm not the only one considering default VGA 256 color palette to be hideous and ugly. What is the story behind this, why were these particular colors chosen?
tuomas's user avatar
  • 2,793
2 votes
2 answers
954 views

RGBI direct connection to VGA display

Theoretically, if I would wire my CGA card output to a proper display using R,G,B,Hsync,Vsync,Ground lines only, I should see something sensible on the screen. I would lose Intesity information, all '...
Dercsár's user avatar
  • 695
13 votes
1 answer
1k views

What are the blinking rates of the caret and of blinking text on PC graphics cards in text mode?

PC display adapters in text mode usually show a blinking cursor on the screen, often in the shape of a bar appearing under the character. Additionally, text may be made to blink by setting an ...
user3840170's user avatar
  • 23.1k
2 votes
0 answers
356 views

Trying To Understand DOS Game Assembly Instructions [closed]

I am trying to understand assembly language instructions, for a DOS Game. I have looked at the following Link :- https://atrevida.comprenica.com/atrtut07.html reading about how VGA Graphics work in ...
Edward Winch's user avatar
18 votes
5 answers
3k views

What is the most accurate way to map 6-bit VGA palette to 8-bit?

AFAIK VGA mode 13h palette has only 64 possible colors (6-bit) per channel. One obvious way to map those 64 colors to 256 colors is to multiply them by 4 (since 4 * 64 = 256): 8_bit = 6_bit * 4; This ...
tigrou's user avatar
  • 689
2 votes
2 answers
559 views

9 pin D-sub to VGA or USB

I've bought a medical device (Giger MD), which collects data during the patient's exercise and send the data to a computer. An UTP cable connects the device to a 9-way D-SUB female, and that should be ...
Erik Fábián's user avatar
5 votes
1 answer
590 views

Is it possible to connect a modern monitor to an 1982 electrical typewriter?

A friend of mine has an electrical typewriter Triumph-Adler BSM 100 SC which is roughly from 1982 (as this site says). The original tube monitor is faded and it's hard to read anything. The VGA video ...
zomega's user avatar
  • 5,372
13 votes
2 answers
1k views

How do I stop flickering in mode 13h?

I'm making a small graphics library for MS-DOS 6.22, using mode 13h with Turbo C on VirtualBox. Recently, I was able to code a small snippet to move a sprite on the screen, using double buffering and ...
SlickSpore's user avatar
4 votes
1 answer
302 views

10 pin --> 26 pin VGA controller pinout and Card compatibility with American Megatrends Super Voyager VLB-III

I'm trying to test an old PC which controls a ABB Bomem FTIR Spectrometer (DA&). The internal PC for this instrument is an American Megatrends, Inc. Super Voyager VLB-III ISA Motherboard https://...
oman's user avatar
  • 43
12 votes
5 answers
5k views

How do 80x25 characters (each with dimension 9x16 pixels) fit on a VGA display of resolution 640x480?

Due to my limited knowledge of retrocomputing and old CRT displays and graphics cards, I could be making some wrong assumptions in this question. For any wrong assumption you find in this question, I ...
Sirius Scientist's user avatar
3 votes
5 answers
3k views

What PC VGA connector used 2 rows of pins?

I remember that 20 years ago (around the year 2000) I came across a few computers with a weird monitor connector. They weren't old computers, but rather budget mainstream computers of the time period. ...
Vilx-'s user avatar
  • 1,485
8 votes
1 answer
1k views

Information about a VGA card named PC-601170-R2

This card is made by Colorgraphic Communications in 1988, and has two VGA ports, and works well with a 80486 computer. I tried to used that with IBM 5150 and other XT clones, but I failed. According ...
Sung's user avatar
  • 509
7 votes
1 answer
526 views

Software that emulated VGA high res mode on an EGA board

I have this very faint recollection from my late elementary school days back in the end of 1980s of a very specific piece of MS-DOS software that claimed to do what was an incredible thing to an ...
mkay's user avatar
  • 699
15 votes
2 answers
2k views

How to use "AND," "OR," and "XOR" modes for VGA Drawing

I've been trying to implement a blitter in MS-DOS, but before I do that I wanted to test the various graphics modes of the VGA graphics card. (I'm emulating using DOSBox.) According to this paper on ...
puppydrum64's user avatar
  • 1,638
21 votes
3 answers
6k views

Why doesn’t my VGA-to-HDMI converter work with my 286 PC?

I have a Commodore PC 30-III with a Cirrus ISA VGA card in it. I wanted to connect to an HDMI display by using a mini VGA-to-HDMI converter The converter doesn't generate any output. The machine ...
Peter Szanto's user avatar
26 votes
7 answers
6k views

How did DOS games manage to have multiple background layers?

Seems like VGA only has one background layer, it appears to be a typical bitmap screen like most home computers of the 80s (Amstrad CPC, Commodore 64 etc.) where each pixel's color is stored in a ...
puppydrum64's user avatar
  • 1,638
7 votes
2 answers
674 views

Monitor can't display boot/DOS video mode making dual boot impossible

I have an HP ZR24w monitor connected via HDMI input to a newer custom machine running Win7, and via VGA input to an older Micron machine running Win98SE. I use the monitor's "source" setting ...
Javic's user avatar
  • 71
42 votes
3 answers
9k views

How do DOS games like DOOM benefit from a PCI graphics card?

The original DOOM and its derivatives (DOOM II, Heretic, Hexen) were early 90s 3D games released at a time when DOS PCs usually had ISA bus Super VGA graphics cards. In the following few years, PCs ...
Brian H's user avatar
  • 60.8k
3 votes
1 answer
352 views

CRT Mitsubishi Diamond Pro 1000 black screen: flashes BIOS logo during boot, but otherwise black

I received this off eBay yesterday and the seller had showed images of it working. The CRT shows many signs of life, I hear static when it turns on, a sound when I switch resolutions, the degaussing ...
Idmi's user avatar
  • 33
1 vote
1 answer
2k views

RGBI to VGA converter [duplicate]

Is there an off the shelf converter / adapter from C128 RGBI to VGA that will work with modern-ish low voltage VGA?
Bartek Malysz's user avatar
11 votes
4 answers
3k views

Physical resolution and control of old VGA (color) CRT monitors

I've just realized I have a gap in my understanding of the VGA CRT monitors of the 80386 era (1980s-1990s). What was the phosphor resolution? It turns out I did not have proper understanding of the ...
Ark-kun's user avatar
  • 211
10 votes
3 answers
2k views

Why does the Amiga 500 have half the HSYNC pulses separately compared to those in CSYNC?

After many years I bought myself a new old Amiga 500 (rev 5) and wanted to hook it up to an LCD monitor (Samsung Syncmaster 152N) that has a VGA input. I tried hooking it up directly by making an ...
durandal's user avatar
  • 103
2 votes
0 answers
545 views

Thinking through the design of a TTL video card: what memory chips and how to manage memory? [closed]

Inspired by Ben Eater's "Let's build a video card" aka "World's worst video card" two part projects on YouTube, I was inspired to consider designing a display adapter for my passive backplane TTL mini-...
Gunther Schadow's user avatar
23 votes
4 answers
4k views

Why was NEC able to wrestle PC graphics standards away from IBM?

The dominant standards for PC graphics in the 1980s were the ones introduced by IBM. This included MDA and CGA with the original IBM PC, followed by EGA shortly after the PC/AT, and then VGA with the ...
Brian H's user avatar
  • 60.8k
13 votes
3 answers
4k views

What DOS games used Mode X as described by Michael Abrash?

In Michael Abrash's Graphics Programming Black Book, many chapters are dedicated to fast drawing of primitives, fills and copies using the 320x240 256-colour Mode X. What MS-DOS games used Mode X? ...
Carr's user avatar
  • 353
7 votes
3 answers
2k views

Commodore monitor to VGA or HDMI

I have this monitor, which I think is a Commodore 64 monitor. I would like to connect it to a pc. Anyone know how to convert VGA or HDMI to this connector format? I've tried searching, but so far I'...
Gertsen's user avatar
  • 173
2 votes
1 answer
783 views

Which retro personal computers, if any, can use a modern day VGA monitor? [closed]

I play around with emulators, but I would love to go back to my roots, with physical ZX81, BBC Micro, Amiga, etc. Unfortunately, those all require a CRT monitor, or a TV, as output. I suppose that I ...
Mawg's user avatar
  • 172
3 votes
3 answers
1k views

VGA controller for my W65C02 computer

I´m planning to build a small computer system, based on the W65C02 from Western Design Center. This computer system should also have a VGA interface with a graphic and a text mode, defined with the ...
Kampi's user avatar
  • 133
35 votes
5 answers
6k views

Why did Super-VGA offer the 5:4 1280×1024 resolution?

Before the age of LCDs, PC displays almost always targeted 4:3 CRT displays. And indeed, VGA and most super-VGA modes had 4:3 aspect ratio resulting in square pixels - except the odd 5:4 1280×1024 ...
Jonathan's user avatar
  • 713
4 votes
1 answer
382 views

What type of video card would be able to drive a VGA monitor that uses a standard HD 15 pin connector with a non VGA standard pinout?

I was browsing old FAQs on the wayback machine1 and noticed that it said some early Mitsubishi Diamond Scan monitors, and reportedly the Dell Ultrascan 17ES monitor2, use a standard HD DE-15 VGA ...
Hitek's user avatar
  • 927
11 votes
2 answers
1k views

Why are my VGA vram to vram copies so slow?

I'm doing some mode x programming and I noticed that my vram to vram copies are much slower than I expected. My copying method was described by Michael Abrash in his Graphics Programming Black Book ...
Luke's user avatar
  • 271
10 votes
3 answers
2k views

Why VGA framebuffer was limited to 64kB window?

VGA framebuffer was fixed to 64kB at A0000h. Right after that there’s MDA/CGA framebuffer at B0000h. I am not sure, but I recall VGA did have to support CGA and its framebuffer, but was there any ...
tuomas's user avatar
  • 2,793
9 votes
3 answers
3k views

What is the best option to connect old computer to modern TV

I was exploring different options of connecting both my Atari ST and C64 to a modern TV. I opted for a composite signal passed through a cheap AV to VGA converter, and although the display works, ...
Bartek Malysz's user avatar
4 votes
1 answer
681 views

Atari 1040ST AV video output - blurred and jagged vertical edges

I have an AV cable that connects Atari 1040STE with a AV to VGA converter. For some reason the vertical edges are not sharp, rather jagged or pixelated. I red that old atari would have an issue with ...
Bartek Malysz's user avatar
2 votes
2 answers
1k views

What are the HSync and VSync frequencies of these common VGA tweak modes?

Most VGA cards and monitors support additional undocumented resolutions, accessed by changing the VGA registers. Most are just variations on the regular modes (320x100 is the same as 320x200, but with ...
Wuerfel_21's user avatar
16 votes
4 answers
4k views

For fast scrolling DOS games, when was Mode13h preferred over Mode X?

Back in the DOS days of gaming (more specifically, 80286 - 80486 era), developers typically needed to choose between using the chunky and easier Mode 13h or the more complex "Mode X" that provided ...
cbmeeks's user avatar
  • 8,531
8 votes
2 answers
1k views

Strange "snow" artifacts when dragging a window in 256-color mode

I picked up a nice Packard Bell Legend 245 over the weekend, and it works great apart from one issue so far: when dragging windows around the screen (Win 3.1), the screen gets corrupted with weird ...
db2's user avatar
  • 1,487
9 votes
4 answers
7k views

How can a Z80/8080/6502 use VGA?

I've come across a couple of projects that manage to get VGA working with the Z80 and similar CPUs: Veronica (6502 CPU, VGA signal generation by AVR) ZC160 (Z80 CPU, VGA signal generation by GAL) c-...
Jet Blue's user avatar
  • 2,005
16 votes
2 answers
7k views

Is the s-video output on the Commodore 64 different from "normal" s-video?

I saw Commodore 64 to modern TV about how to connect the Commodore 64 to a modern TV. I don't understand all the details of the answer, so I wanted to try and ask something specific here. In short, I ...
Thomas's user avatar
  • 385
19 votes
7 answers
5k views

What video connections were common in Europe?

What video connections were common on European TVs and monitors during the "retro" era? In the USA, first there were none on TVs (RF screw terminals only) and monitors had composite (yellow RCA, CVBS)...
snips-n-snails's user avatar
4 votes
1 answer
397 views

Does a final version of the IBM VGA XGA Technical Reference Manual exist?

I'm doing some bare metal programming and I'm getting a lot of information from the IBM VGA XGA Technical Reference Manual May92 document. The only reference I can find about this document, is this ...
Stijn's user avatar
  • 143
19 votes
3 answers
4k views

Do all VGA cards implicitly support CGA and EGA?

Practically speaking, if I buy an ISA VGA card, will it implicitly support CGA and EGA games?
Sydius's user avatar
  • 2,634
11 votes
5 answers
3k views

Invert LCD screen in DOS 5.0

Would like to run "black on white" software on a DOS machine with an LCD screen, so am wondering if there are any TSR tools, or similar, for inverting the screen. I believe it is grey scale VGA, not ...
Tomas By's user avatar
  • 2,102
8 votes
3 answers
1k views

Choosing a VGA card for the IBM 5162?

When shopping for a VGA ISA card, how might I know if it would be compatible with an IBM 5162? Do all 8-bit and 16-bit ISA VGA cards work, or only some?
Sydius's user avatar
  • 2,634
4 votes
1 answer
467 views

Which graphics adapters outputted S-Video over VGA?

To this day you can buy passive cables which separate out S-Video and composite signals from VGA. There's always a warning to check whether your graphics adapter output these over the VGA connector. ...
chx's user avatar
  • 1,041
13 votes
3 answers
2k views

Acorn Electron to VGA/HDMI?

I am aware that there are answers regarding this but they do not seem to answer it for me. A few years back I got a Acorn Electron and it works using the arial for video fine, but I would like to ...
Antony's user avatar
  • 131
12 votes
6 answers
7k views

Converting SCART to VGA/Jack

I have a few home-microcomputers that use SCART to output both audio & video to TV screens such as the Atari STE 1040 and the Sony MSX Hitbit 501. I don't have room to store old cathode-ray ...
Informancien's user avatar
  • 2,657