" by Chris Smith is the definitive guide. It contains over 140 illustrations and reverse-engineered circuit diagrams.
:
Designing a retro microcomputer based on the ZX Spectrum architecture requires mastering the , the custom chip responsible for video generation, memory management, and I/O. Core Architecture of the ZX Spectrum ULA " by Chris Smith is the definitive guide
| Criteria | FPGA | RP2040 | Discrete 74HC | |----------|------|--------|----------------| | Cycle accuracy | ✅ Exact | ⚠️ Approx | ✅ Exact | | PCB size | Tiny (QFP) | Tiny | Huge (15×10 cm) | | Power consumption | Low (~80 mA) | Low (~100 mA) | High (>300 mA) | | Development effort | Medium | Low (software) | Very high | | Authenticity | High (hardware) | Emulation | Exact but large | | Suitable for portable? | ✅ Yes | ✅ Yes | ❌ No | Core Architecture of the ZX Spectrum ULA |
The 40-pin ULA (specifically the 6C001E-7 in the Issue 2 board) performs five critical functions that define : " by Chris Smith is the definitive guide
