ChipsI/O & supportParallel I/O (PIA/VIA/PPI) › MOS 6526 CIA

MOS 6526 CIA

1982

MOS Technology's Complex Interface Adapter, combining I/O ports, timers and a time-of-day clock in the Commodore 64 and Amiga.

Machines

Operating systems

Reference & documentation

External technical references for programming MOS 6526 CIA and for writing emulators.

ResourceTypeNotes
MOS 6526 CIA Preliminary Datasheet (Nov 1981) ↗DatasheetOriginal MOS datasheet: registers, timing, electrical specs
CIA 6526 Register Reference (oxyron.de) ↗Memory mapAll 16 registers with per-bit definitions
CIA - C64-Wiki ↗Memory mapCIA1/CIA2 register map at $DC00/$DD00
MOS 6526 CIA Preliminary Datasheet (Nov 1981) ↗Pinout40-pin DIP pin configuration and signal descriptions
MOS Technology CIA - Wikipedia ↗PinoutPin diagram plus 6526/6526A/6526B/8520 variant overview
A Software Model of the CIA6526 (Wolfgang Lorenz) ↗ProgrammingCycle-exact timer, ICR and pipeline behavior for emulators
Detecting 6526 vs 6526A CIA Chips (Codebase64) ↗ProgrammingCycle-timing routine distinguishing 6526 revisions
CBM Chip Data Documents Directory (zimmers.net) ↗ReferenceDatasheets, 8520 variant, and CIA internals archive
CIA6526 C++ Implementation (Lorenz) ↗SourceReference C++ CIA model source code
Wolfgang Lorenz CIA6526 Reverse-Engineering Package ↗Test suiteIncludes emulator conformance test programs for the CIA