The Zx Spectrum Ula How To Design A Microcomputer Zx Design Retro Computer Portable ((install))

┌─────────────────────────────────────────┐ │ 3.7V Li-ion Battery │ │ (2000 mAh) │ └──────────────┬──────────────────────────┘ │ 3.7V ┌─────▼─────┐ │ Boost │ │ 3.7V→5V │ └─────┬─────┘ │ 5V ┌──────────┼──────────────────────────┐ │ ▼ │ │ ┌────────────┐ │ │ │ FPGA │ │ │ │ (iCE40) │◄────┐ │ │ │ ULA + │ │ │ │ │ glue logic │ │ │ │ └─────┬──────┘ │ │ │ │ 3.5 MHz │ │ │ ▼ │ │ │ ┌────────────┐ │ │ │ │ Z80 │ │ Data/Address │ │ │ (CMOS) │────┼──────────────┘ │ └─────┬──────┘ │ │ │ │ │ ┌─────▼──────┐ │ │ │ 64KB SRAM │ │ │ │ (AS6C62256)│ │ │ └────────────┘ │ │ │ │ ┌────────────┐ │ │ │ LCD │ │ │ │ 320×240 │◄───┘ (RGB + sync) │ │ (Parallel) │ │ └────────────┘ │ │ ┌────────────┐ │ │ SD Card │ │ │ (SPI mode) │ │ └────────────┘ └─────────────────────┘

The result isn't a "clone" – it's a that fits in your pocket, boots instantly, runs original software (via .tap/.z80 files), and respects the spirit of the original: clever hardware design that punches above its weight. Discrete Logic (The "Harlequin" Method) An FPGA (e

: These often use a matrix-wired tactile keyboard connected to the microcontroller's I/O pins. Creating a Portable "Pocket" Design Amazon

To build a functional clone or inspired design today, you have three primary paths: 1. Discrete Logic (The "Harlequin" Method) and memory management—into a single

An FPGA (e.g., Lattice iCE40 UP5K or Sipeed Tang Nano) can replicate the ULA’s parallel logic exactly.

. This chip combined disparate logic functions—video generation, keyboard scanning, and memory management—into a single, cost-effective package. Amazon.com The Role of the ULA in ZX Design The ULA was the bridge between the