Questions tagged [cga]

For questions related to the IBM Color/Graphics Adapter signals, sources, or receivers.

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19
votes
7answers
4k 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)...
16
votes
2answers
2k views

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?
12
votes
2answers
559 views

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: ...
9
votes
5answers
2k views

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?
7
votes
2answers
812 views

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,...
3
votes
3answers
171 views

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?
3
votes
1answer
339 views

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. ...
1
vote
1answer
136 views

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 ...
0
votes
1answer
236 views

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?