Chips › I/O & support › Custom & glue logic › Sinclair ULA
Sinclair ULA
1982
Sinclair's custom Uncommitted Logic Array, the single gate-array chip that handled video, memory and I/O in the ZX Spectrum.
Machines
Emulators
| Emulator | Type | License | Site |
|---|---|---|---|
| EightyOne | downloadable | GPL-3.0 | Website ↗ |
| ElectrEm | downloadable | GPL-2.0 | Website ↗ |
| ElkJS | online | GPL-2.0 | Website ↗ |
| Elkulator | downloadable | GPL-2.0 | Website ↗ |
| FBZX | downloadable | GPL-3.0 | Website ↗ |
| Klive IDE | downloadable | MIT | Website ↗ |
| Qaop/JS | online | Freeware | Website ↗ |
| RealSpectrum | downloadable | Freeware | Website ↗ |
| Retro Virtual Machine | downloadable | Freeware | Website ↗ |
| SpecEmu | downloadable | Freeware | Website ↗ |
| Speccy | downloadable | Freeware | Website ↗ |
| SpectNetIDE | downloadable | MIT | Website ↗ |
| Spectaculator | downloadable | Commercial | Website ↗ |
| Spectral | downloadable | MIT | Website ↗ |
| Unreal Speccy Portable | both | GPL-3.0 | Website ↗ |
| UnrealSpeccy | downloadable | GPL-3.0 | Website ↗ |
| Warajevo | downloadable | Freeware | Website ↗ |
| Xpeccy | downloadable | GPL-3.0 | Website ↗ |
| ZEsarUX | downloadable | GPL-3.0 | Website ↗ |
| ZX Spin | downloadable | Freeware | Website ↗ |
| zxsp | downloadable | BSD-2-Clause | Website ↗ |
Reference & documentation
External technical references for programming Sinclair ULA and for writing emulators.
| Resource | Type | Notes |
|---|---|---|
| ZX Spectrum ULA - Sinclair Wiki ↗ | Datasheet | 40/48-pin diagrams and per-model signal detail |
| Contended memory - Sinclair Wiki ↗ | Memory map | T-state contention tables for every Spectrum model |
| ZX Spectrum ULA pinout - AllPinouts ↗ | Pinout | Complete 40-pin ULA pinout with signal functions |
| Floating bus technical guide ↗ | Programming | Floating-bus cycle timing for flicker-free display sync |
| ZX Spectrum ULA - Sinclair Wiki ↗ | Reference | Definitive ULA function, revisions, snow effect, timing |
| ZX Spectrum ULA Types - Spectrum for Everyone ↗ | Reference | Catalogue of ULA revisions and part numbers |
| Sinclair ZX Spectrum Service Manual ↗ | Schematic | Full service manual schematics showing ULA wiring |
| ULA chip for ZX Spectrum - OpenCores ↗ | Source | FPGA-proven Verilog ULA core, GPL |
| freecores/zx_ula - GitHub ↗ | Source | ULA Verilog source, CPLD and FPGA versions |
| ZX Spectrum Timing Tests ↗ | Test suite | 35-test Z80/ULA contention conformance suite |