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Intel 8253 PIT
1978
Intel's Programmable Interval Timer, supplying three counters used for timing and the speaker tone in the IBM PC.
Reference & documentation
External technical references for programming Intel 8253 PIT and for writing emulators.
| Resource | Type | Notes |
|---|---|---|
| Intel 8254 Programmable Interval Timer Datasheet (231164-005) ↗ | Datasheet | Canonical Intel datasheet: modes, control word, AC/DC timing |
| Intel 82C54 CHMOS Programmable Interval Timer Datasheet (231244-006) ↗ | Datasheet | CMOS variant datasheet with full timing waveforms |
| Programmable Interval Timer - OSDev Wiki ↗ | Memory map | I/O port map 0x40-0x43 and channel assignments |
| Intel 8254 Programmable Interval Timer Datasheet (231164-005) ↗ | Pinout | Pin descriptions and package diagrams for 8254 |
| Programmable Interval Timer - OSDev Wiki ↗ | Programming | Emulator/OS-oriented 8253/8254 programming reference |
| 8253 Timer - HelpPC Reference ↗ | Programming | Concise port and control-register bit reference |
| Intel 8253 - Wikipedia ↗ | Reference | Overview: counters, modes, PC usage, variants |
| MAME pit8253.cpp - 8253/8254 Emulation Source ↗ | Source | Accurate C++ implementation of all six modes |
| VirtualBox DevPit-i8254.cpp - PIT Emulation Source ↗ | Source | QEMU-derived C 8254 emulation with speaker port |