Chips › I/O & support › Storage controllers › NEC uPD765 FDC
NEC uPD765 FDC
1979
NEC's floppy disk controller, the chip behind the IBM PC's diskette interface and many other 1980s computers.
Machines
Operating systems
Emulators
| Emulator | Type | License | Site |
|---|---|---|---|
| Anex86 | downloadable | Freeware | Website ↗ |
| CP/M Box | online | Freeware | Website ↗ |
| Joyce | downloadable | GPL-2.0 | Website ↗ |
| M88 | downloadable | Freeware | Website ↗ |
| NP2kai | both | BSD-3-Clause | Website ↗ |
| Neko Project 21/W | downloadable | BSD-3-Clause | Website ↗ |
| Neko Project II | downloadable | BSD-3-Clause | Website ↗ |
| QUASI88 | downloadable | BSD-3-Clause | Website ↗ |
| T98-Next | downloadable | Freeware | Website ↗ |
| XM8 | downloadable | Freeware | Website ↗ |
Reference & documentation
External technical references for programming NEC uPD765 FDC and for writing emulators.
| Resource | Type | Notes |
|---|---|---|
| NEC µPD765A/765B Floppy Disc Controller Datasheet (HTML) ↗ | Datasheet | Full NEC datasheet: all 16 commands, phases, status registers |
| NEC uPD765 Data Sheet (Dec 1978, bitsavers scan) ↗ | Datasheet | Original NEC scan: electrical, timing diagrams, commands |
| NEC uPD765 Application Note (Mar 1979, bitsavers) ↗ | Datasheet | NEC app note: interface circuits, PLL, write precomp |
| NEC µPD765A/765B Floppy Disc Controller Datasheet (HTML) ↗ | Instruction set | Byte-level command/parameter/result encoding for all commands |
| NEC µPD765A/765B Floppy Disc Controller Datasheet (HTML) ↗ | Pinout | 40-pin DIP configuration and signal descriptions |
| NEC uPD765 Data Sheet (Dec 1978, bitsavers scan) ↗ | Pinout | Original pin configuration and AC timing parameters |
| Programming the NEC µPD765 and Intel 82072/7 FDC ↗ | Programming | Registers, DMA/IRQ6, 13+4 commands with assembly examples |
| µPD765A Disc Controller Primer - Muckypaws ↗ | Programming | Z80 hands-on: recalibrate, seek, read/write, format |
| 765 FDC - CPCWiki ↗ | Reference | Community reference documenting quirks and undocumented behavior |
| Programming Floppy Disk Controllers - Ardent Tool ↗ | Reference | DOR/MSR/status registers and full command set breakdown |
| HelpPC: NEC µPD765 / 8272A Floppy Controller ↗ | Reference | Quick reference: registers, ports 3F0h-3F7h, 15 commands |
| floooh/chips - upd765.h emulator ↗ | Source | Clean C header FDC emulation: phases, FIFO, callbacks |