Game 5 Unit 21 of 128 1 hr learning time

Title Music

Add a simple beeper melody that plays on the title screen, creating atmosphere and a sense of completeness.

16% of Ink War

Music sets the mood. Even a simple beeper melody makes the title screen feel complete.

Run It

Assemble and run:

pasmonext --sna inkwar.asm inkwar.sna

Unit 21 Screenshot

Version shows “PHASE 2 V0.5”. Listen for the melody on the title screen.

Beeper Music Challenges

The Spectrum beeper has limitations:

ChallengeSolution
No hardware timerSoftware timing loops
Single channelOne note at a time
CPU-boundBrief notes, gaps for input checking
No volume controlRhythm through silence

Non-Blocking Music

The key is playing short notes with gaps:

play_title_music:
            ; Check timer
            ld      a, (music_timer)
            or      a
            jr      z, .play_note

            ; Still waiting - decrement and return
            dec     a
            ld      (music_timer), a
            ret

.play_note:
            ; Reset timer for next note
            ld      a, 12               ; 12 frames = 0.24 sec
            ld      (music_timer), a

            ; Play current note...

This allows the game to remain responsive between notes.

Melody Data

Store pitch values in a table:

title_melody:
            defb    30, 35, 30, 40      ; Rising/falling pattern
            defb    35, 30, 40, 35
            defb    30, 35, 30, 45
            defb    40, 35, 30, 25
            defb    0                   ; End marker (loops)

Higher values = lower pitch (longer delay between beeper toggles).

Note Playback

Play a brief tone without blocking too long:

            ld      c, a            ; Pitch value
            ld      b, 8            ; Very short duration

.tone:
            push    bc
            ld      a, $10
            out     (KEY_PORT), a   ; Beeper on
            ld      b, c
.d1:        djnz    .d1             ; Pitch delay
            xor     a
            out     (KEY_PORT), a   ; Beeper off
            ld      b, c
.d2:        djnz    .d2
            pop     bc
            djnz    .tone

Eight cycles keeps each note brief.

The Complete Code

What You’ve Learnt

  • Non-blocking music - Play notes without freezing input
  • Timer-based sequencing - Use frame counters for note timing
  • Melody data format - Simple pitch tables with loop markers
  • Beeper limitations - Working within hardware constraints

What’s Next

Unit 22 adds an options menu for configuring game settings.

What Changed

Unit 20 → Unit 21