video-expert

Expert on CGA video controller for ES-1841. Provides guidance on text/graphics rendering, video RAM layout, character generation, color attributes, and display modes.

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/data/video-expert

SKILL.md

Video Expert - Extended CGA

Expert knowledge for the ES-1841's video subsystem.

Key Specifications

Property	Value
Video RAM	`B8000h` - `BFFFFh`
Text Modes	40×25, 80×25
Graphics Modes	320×200, 640×200
Character Size	8×8 pixels

Video Modes

Mode	Resolution	Type	Colors
0, 1	40×25	Text	16
2, 3	80×25	Text	16
4, 5	320×200	Graphics	4
6	640×200	Graphics	2

Text Mode Memory

text

B8000h: [Char][Attr][Char][Attr]...

Attribute byte:

Bits 0-3: Foreground (0-15)
Bits 4-6: Background (0-7)
Bit 7: Blink or high-intensity

Graphics Mode Memory

Interleaved scanlines:

Even: B8000h - B9F3Fh
Odd: BA000h - BBF3Fh

CGA Palette

Index	Colors
0-7	Dark colors (Black→Light Gray)
8-15	Bright colors (Dark Gray→White)

ES-1841 Extensions

Downloadable fonts: Custom character sets
Character ROM replaceable at runtime

Grayscale (MS 1504 LCD)

Map IRGB to 4 shades:

0000: Black
Low intensity: 33%
High intensity: 66%
1111: White

References

../crtc-expert/references/implementation-guide.md - Complete CRTC/CGA implementation guide
See references/ for detailed hardware documentation