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IBM CGA

1981

IBM's 1981 Color Graphics Adapter, the first colour display standard for the IBM PC.

Machines

IBM PC 5150

IBM PC/XT

IBM PCjr

Operating systems

DR-DOS 5.0

DR-DOS 6.0

MS-DOS 1.0

MS-DOS 3.3

MS-DOS 5.0

MS-DOS 6.22

Windows 1.0

Emulators

EmulatorTypeLicenseSite
8086tinydownloadableMITWebsite ↗
BochsdownloadableLGPL-2.1Website ↗
BoxerdownloadableGPL-2.0Website ↗
DOSBox ECEdownloadableGPL-2.0Website ↗
DOSBox PuredownloadableGPL-2.0Website ↗
DOSBox StagingdownloadableGPL-2.0Website ↗
DOSBox-XdownloadableGPL-2.0Website ↗
DOSEMU2downloadableGPL-2.0Website ↗
Fake86downloadableGPL-2.0Website ↗
MartyPCbothMITWebsite ↗
PCE / PCE.jsbothGPL-2.0Website ↗
PCemdownloadableGPL-2.0Website ↗
PCjsonlineMITWebsite ↗
XTulatordownloadableGPL-2.0Website ↗
em-dosboxonlineGPL-2.0Website ↗

Reference & documentation

External technical references for programming IBM CGA and for writing emulators.

ResourceTypeNotes
Motorola MC6845 CRTC Datasheet ↗DatasheetOfficial 6845 CRTC datasheet: registers, pinout, timing.
Colour Graphics Adapter Notes (Seasip) ↗Memory mapInterleaved graphics memory layout across 16KB.
Colour Graphics Adapter Notes (Seasip) ↗ProgrammingEvery CGA port, register bit, and mode.
MC6845 CRTC Simplifies Video Displays (Motorola AN-0851) ↗ProgrammingMotorola app note on programming the 6845.
Exploring CGA Wait States (MartyPC) ↗ReferenceCycle-exact CGA memory wait-state algorithm derived.
CGA - The PC Emulation Book (MartyPC) ↗ReferenceEmulator author's detailed CGA implementation reference.
IBM's CGA Hardware Explained (Nerdly Pleasures) ↗ReferenceModes, registers, snow, and RGBI color decoding.
8088 MPH Final: Old vs New CGA ↗ReferenceComposite color generation and CGA revision differences.
IBM Color/Graphics Monitor Adapter Manual ↗SchematicIBM option manual: full CGA schematics and specs.
CRTC Emulation for MESS (Reenigne) ↗SourceCycle-exact 6845 emulation design and raster effects.