Zx Spectrum Test Program Apr 2026

Just finished a little weekend project – a bare-bones ZX Spectrum diagnostic/test program written in Z80 assembly. Thought I’d share it for anyone restoring old rubber-keyed Speccys or building a clone (like a Harlequin or ZX-UNO).

Here’s a retro-computing style post for a forum, social media, or blog, depending on where you want to share it. Building a Simple Test Program for the ZX Spectrum – Check RAM, ROM, and Keyboard in under 1KB zx spectrum test program

Should I add a ULA snow test or an AY-3-8910 sound check next? Anyone else have a favourite minimal test routine? Just finished a little weekend project – a

ZX TEST v1.0 ROM CHK: PASS RAM 48K: PASS KB TEST: Press any key... I’ve put the .tap file and source on GitHub → [link] Building a Simple Test Program for the ZX

#ZXSpectrum #RetroComputing #Z80 #Diagnostics #Homebrew

ld hl, 32768 ; start of 32K RAM area (for 48K) ld de, 32769 ld bc, 32768-1 ld (hl), $FF ldir ; fill with $FF ; ... then verify and repeat with $00, $AA, $55