The Zx Spectrum Ula How To Design A Microcomputer Zx Design Retro Computer Portable ✓

Inside the ZX Spectrum ULA & How to Design a Portable Retro Microcomputer

Color is applied in 8x8 pixel blocks. This "limitation" defines the retro aesthetic. 🔋 Making it Portable

ROM: 16KB or 32KB ROM(s) for BASIC/firmware; store alternate ROMs (48K BASIC, 128K + AY drivers) in SPI flash or on SD and boot-selectable.

After six months of burnt fingertips and thousands of lines of code to simulate the ULA's video timing, the moment arrived. He flicked the toggle switch. Inside the ZX Spectrum ULA & How to

• Use an FPGA (e.g., Lattice iCE40/ ECP5 or small Xilinx Spartan) to implement Spectrum ULA logic: video timing, attribute fetch, contention/timing, floating bus behavior, bus contention with CPU, keyboard matrix, beeper/pulse generation, memory contention for 128K machines, and tape I/O timing.
• Advantages: cycle-accurate timing, replicates quirks needed by demos/games.

2. Portable Form Factor