If you are using an , write a video controller module in Verilog. Use a pixel counter to read these memory locations sequentially, synchronizing the data stream to match modern VGA or SPI display panel timings.
use FPGAs to run "cores" that simulate the ULA and Z80 with high accuracy.
The original ULA produced 1-bit "beeper" sound. You can easily route this digital signal through a simple low-pass filter to a headphone jack or a small internal speaker. Step 3: Power Management for Portability If you are using an , write a
To design your own microcomputer or clone the Spectrum, you must understand the four primary pillars of the ULA's architecture: Video Signal Generation (The Pixel Engine)
While not pure hardware emulation, high-speed microcontrollers can run software emulators fast enough to simulate the ULA and Z80, outputting video directly to an LCD. 2. Video Processing for Portable Screens The original ULA produced 1-bit "beeper" sound
Design a custom 4-layer PCB using software like KiCad. Keep track traces short around the high-frequency crystal oscillator to prevent digital noise in your audio and video paths. The Legacy of ZX Design
The Spectrum's 40-key matrix keyboard is legendary but difficult to use on the go. When designing a handheld version, you can implement a tactile dome switch membrane or use a smaller blackberry-style QWERTY keyboard matrix, mapping the original Spectrum key lines to your modern ULA input registers. The Legacy of the Open-Source Spectrum Instead of sequential rows
The ULA maps a 256×192 pixel grid using an incredibly non-linear memory layout. Instead of sequential rows, the memory is interleaved to optimize how the ULA’s internal counters cycle through addresses.
A separate 32x24 grid dictates the colors (attributes) for each 8x8 pixel block.
The ULA was responsible for almost all the critical infrastructure of the computer: