Sinclair ZX Spectrum

Production-ready patterns for Sinclair ZX Spectrum development

Patterns

Rendering

3 patterns

Write colours directly to attribute memory for fast, flicker-free graphics without touching pixel data.

Print ASCII characters to the screen using the ROM character set. Direct display file access for fast text rendering.

Convert a number (0-99) to two ASCII digits and print them. Essential for scores and counters.

1 pattern

Read the ZX Spectrum keyboard matrix by polling I/O ports. Simple, efficient, and no ROM routines required.

1 pattern

Generate a simple beep or tone by toggling the speaker bit. Rising or falling pitch for feedback sounds.

1 pattern

Move an entity on a grid with boundary checking. Prevents moving outside the play area.

2 patterns

Frame-synchronised game loop using the HALT instruction. Locks to 50Hz for consistent timing across all Spectrums.

Organise game flow with distinct states (title, playing, game over). Clean separation of game phases.