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Hitachi HD6845

1980

Hitachi's second-source version of the 6845 CRT controller, generating video timing and addressing in many 1980s computers and terminals.

Reference & documentation

External technical references for programming Hitachi HD6845 and for writing emulators.

ResourceTypeNotes
Hitachi HD6845R/HD6845S CRTC Datasheet ↗DatasheetOfficial Hitachi datasheet: registers, timing, electricals
Motorola MC6845 CRTC Datasheet ↗DatasheetOfficial 6845 CRTC datasheet: registers, pinout, timing.
BeebWiki: CRTC Register Map ↗Memory mapFull R0-R17 register/bit map and status
Hitachi HD6845 Datasheet - Pinout ↗Pinout40-pin package pin assignments and signals
Motorola MC6845 CRTC Programming Reference ↗ProgrammingRegister formulas, worksheets, init code examples
MC6845 CRTC Simplifies Video Displays (Motorola AN-0851) ↗ProgrammingMotorola app note on programming the 6845.
Differences of CRTC models (6845/6545/HD46505) ↗ReferencePer-model register/status quirks vital for emulation
CRTC 6545/6845 Operation Overview ↗ReferenceRegister access, timing model, interlace, status bits
Motorola 6845 - Wikipedia ↗ReferenceOverview, register table, Hitachi HD46505 variants
CRTC Emulation for MESS (Reenigne) ↗SourceCycle-exact 6845 emulation design and raster effects.
mc6845.c CRTC emulation (C source) ↗SourceWorking C implementation of 6845 registers