Audio Patterns
Music playback, sound effects
Commodore 64
3 patternsSID Multi-Voice
Step a note pattern once per raster interrupt, handing each of the SID's three voices its note from a frequency table — the skeleton of every C64 music player.
SID Note Trigger
Play a single note on the SID chip with gate control. The foundation of all SID audio.
SID Voice Setup
Configure a SID voice with frequency, waveform, and ADSR envelope. Foundation for all SID audio programming.
Sinclair ZX Spectrum
5 patternsAY Envelopes and Noise
Let the AY shape a note's volume in hardware and add its noise channel — a decaying pluck from the envelope generator, an explosion from noise, each fired with a single register write.
AY Music
Step a note pattern once per interrupt, handing each of the AY's three channels its note from a period table — a full three-voice tune that plays in the background while the game runs.
AY Tone
Play a tone on the 128K's AY-3-8912 sound chip — select a register through port $FFFD, write it through $BFFD, and the chip holds the note on its own while the CPU gets on with the game.
Beeper Music
Play an actual melody on the Spectrum's one-bit speaker — a note table for pitch, a length per note — and coax two or more voices from that single bit with phase accumulators.
Sound Beep
Generate a simple beep or tone by toggling the speaker bit. Rising or falling pitch for feedback sounds.
Nintendo Entertainment System
3 patternsA Music Engine
Step a note pattern once per frame from the NMI, handing each APU channel its note from a timer table — the skeleton of every NES music driver.
A Square Wave
Enable one of the NES APU's pulse channels, set its duty, volume and 11-bit timer, and it holds a tone on its own — the foundation of every NES sound.
Sound Effects
Let the APU bend pitch and fade volume in hardware — a swept pulse for a laser, a decaying noise burst for an explosion — each fired with a single trigger write.
Commodore Amiga
3 patternsFour-Channel Music
Drive all four of Paula's channels from a note sequence, stepping the pattern on a timer interrupt and turning note numbers into periods — the skeleton of every Amiga tracker and MOD player.
One-Shot Samples
Play a sample once instead of looping, using Paula's channel interrupt to stop it after a single pass — the way sound effects fire, and the seed of tracker playback.
Playing a Sample
Point one of Paula's four audio channels at an 8-bit sample in chip RAM, set its pitch and volume, and let DMA play it — the foundation of all Amiga sound.
Cross-Platform
2 patternsFour Ways to Make a Sound
The tune driver is the same on every machine — but what it talks to isn't. Paula streams a sample, the APU synthesises fixed voices, the SID shapes a rich one, and the Spectrum toggles a single bit. Four answers to 'how does a computer make a sound?', and each one shaped the music.
Tune Sequencer with Two Terminators
A melody is a table of pitch and duration; a once-per-frame tick serves it. One terminator loops (title music), the other stops (fanfares and stings) — win and lose having voices costs one extra marker.