The year was 1982, and the air in Richard’s workshop was thick with the scent of solder and ozone. On his desk sat a "dead" ZX Spectrum
Recreating the ZX Spectrum experience hinges on reproducing both function and timing. Using an FPGA to implement a modern ULA lets you preserve the machine’s behavioral quirks (what made the Spectrum special) while adding modern conveniences for portability. Start with a focused FPGA video/DRAM prototype, iterate with a simple ROM and Z80 core, and build outward—balancing authenticity and usability to produce a compact, lovable retro microcomputer. The year was 1982, and the air in
to emulate the Z80. This is easier for portable builds as it handles power management better. 2. Replacing the ULA Using an FPGA to implement a modern ULA
When designing a modern "retro" microcomputer or a portable handheld, you have three primary paths to replicate or replace the original ULA: 1. The FPGA Approach Modern implementations like the ZX Spectrum Next Field-Programmable Gate Arrays (FPGAs) to recreate the ULA's logic. Advantages: This is easier for portable builds as it
(CMOS version). It still runs at 3.5MHz and is widely available.
use the Pico to emulate the Z80 and ULA in software, outputting to a small IPS display. Portability:
It has: