Questions tagged [cga]
IBM Color Graphics Adapter: signals, sources and receivers.
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Why weren't there games that use CGA 16-color low res mode?
The very first PC could do stuff only seen in arcade games, like graphics mode vertical scrolling.
It involved a little known 160 x 100 video mode called "lores" that was almost ...
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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 ...
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Why weren't CGA colors selectable from palette?
Most memorable graphics mode in games for CGA was 320x200 which supported 4 colors. (I know there was 16 color composite mode trick, but let's ignore that.)
Those 4 colors could be selected from ...
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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 '...
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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 ...
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Converting CGA (from Commodore PC40) to RetroTink 5X?
I am quite new to the CGA world but I recently got hold on a Commodore PC40-01 desktop computer. This has a CGA card but how to connect this to my RetroTink 5X-Pro, so I can get it to be displayed on ...
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Is it possible to detect a CGA card on an IBM PC 5150 by write/reading the Motorola 6845?
I am trying to programatically detect the CGA card on old IBM 5150-ish PCs.
The Paku Paku game source code doesn't directly detect it. The strategy is to detect VGA, EGA, Tandy, PCJr, etc etc, then if ...
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How did the IBM 5153 color display detect and modify the signal to make low-intensity yellow into "brown"?
The IBM CGA video card generated 16 colours indicated via four binary TTL signals: R, G, B and I (red, green, blue and intensity). This was not an entirely linear transformation: in particular, RGBI=...
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What is an XRGB video signal? (NOT the modern XRGB mini-DIN.)
I have a mid-1980s CRT monitor, a C. Itoh Chroma Pro CM1000, with an 8-pin DIN RGB input that's visually similar to the digital RGB input on a Commodore 1084. The input is selectable between "RGB,...
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What really prevented PC games from using hardware scrolling on CGA
According to https://en.wikipedia.org/wiki/Adaptive_tile_refresh:
CGA (the previous generation of PC graphics hardware) lacks features for scrolling in hardware
so PC games started featuring ...
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Is it possible to convert a Tandy 1000 EX video signal to SCART?
I've recently acquired a Tandy 1000 EX. It appears to have a 9 pin RGB video out and I understand it produces a CGA signal. I would like to connect this output to my SCART switcher, which is connected ...
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Could CGA synchronize with vertical blank?
According to http://www.vcfed.org/forum/showthread.php?62049-The-myth-of-the-vertical-retrace-interrupt-on-EGA-VGA
IBM first implemented a vertical retrace interrupt on the PCjr in 1984.
That ...
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Was there ever a functional EGA emulator for the Hercules graphics card?
I used to use a CGA emulator (don't remember which one it was), that could show some gfx even in EGA/VGA-only games (when I selected EGA mode). I remember my frustration seeing some garbled graphics ...
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How do I configure a V6366 graphics controller for 640x400 B/W?
I have here a Schneider Target PC 7640 which is an early PC AT compatible laptop. It features a 640x400 plasma screen with 32k display RAM driven by a Yamaha V6366 B-F graphics controller.
I was ...
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Motorola 6845 and bitwise graphics
I'm curious about how graphics were drawn on systems using the Motorola 6845. I understand this was used in the CGA? If so, did the 6845 really work bitwise, was the bitwise graphics entirely separate,...
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Is the IBM 5153 color display compatible with the Tandy 1000 16 color modes?
Is it possible to view games made for Tandy Graphics (TGA, etc) on an IBM 5153 color display connected to an original Tandy 1000 (or 1000/A) in 16 colors?
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Why did CGA RGBI output leave DAC to the monitor?
CGA on the original IBM PC produced sixteen colors, one bit each for red, green, blue and overall intensity modifier.
The preferred output device was the later-arriving 5153 color monitor, which ...
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How to use the "darker" CGA palette using x86 Assembly?
For those of you retro developers out there, I am having a hard time figuring out how exactly to select the "darker" color palette in 320x200 CGA mode. Here's what I have so far:
setup_cga_graphics:
...
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VGA to CGA (RGBI) signal
Does anybody know how I can go from an analog RGB signal to a TTL RGBI signal?
Is there a good circuit for this out there somewhere?
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How do CGA emulators for Hercules graphics work?
HGC cards on IBM PCs used to be able to run CGA software by using a CGA emulator. How exactly did those programs work? What were the limitations?
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IBM 5153 monitor vertical resolution
The IBM 5153, the color monitor accompanying the original IBM PC, was designed to work with the CGA graphics card, vertical resolution 200 scan lines. This was quite unsurprising and straightforward.
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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)...
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How can I adapt a digital CGA/C128 signal (RGBI DE-9) to a modern monitor?
IBM's CGA and the Commodore 128's RGB video output both use a DE-9 connector. How do I adapt the CGA video output from an IBM XT 5160 or Commodore 128 to a modern monitor?
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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?
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