Code Like It's 198x

Trigger a sound on Dragon 32

Reuse a small real effect, understand who stops it, and compare its native output with an omitted-trigger control.

Give an accepted action a sound. The same caller changes its picture and triggers this effect; a second version performs the action with the trigger removed. Listen to both.

Working effect

Trigger omitted

Take the effect

The reusable effect

sound.bas
2000 SOUND 100,2
2010 RETURN

SOUND 100,2 uses the ROM sound routine and blocks while it generates the tone. Those operands are BASIC pitch/duration units, not frequency and seconds.

Copy the 2000-range subroutine and call GOSUB 2000 when the game accepts an action. Keep its global scratch variables and any DATA/setup lines with it. A sound call is a consequence of an action, not a substitute for input validation.

Change it and recognise a mistake

Change the SOUND operands using the language manual’s ranges. A non-blocking player would need to take over the audio path and its timing.

The omitted-trigger control still accepts the action but fails the same audio guard as the working caller. Keyboard clicks or other machine output are not enough: the BASIC checks compare against a separate rejected-command recording.

Deliberately omitted sound trigger

no-sound.bas
10 N=0
20 CLS:PRINT "TURN";N
21 GOSUB 1000
30 GOSUB 3000
40 IF A=1 THEN N=N+1
50 GOTO 20
1000 PRINT "XXX"
1010 PRINT "X X"
1020 PRINT "XXX"
1030 RETURN
2000 SOUND 100,2
2010 RETURN
3000 INPUT A
3010 RETURN

The working implementation above repairs that omission. If an effect instead drones on, check the mute/service path and that its state is initialised. Servicing twice makes a counted effect shorter; servicing only after input can leave it running while the player waits. Those are lifecycle decisions to test when adapting it.

Run the caller

Enter the complete demo.bas in Dragon 32 BASIC and RUN. Submit 1, then Return. One accepted command advances the displayed turn; another gives two.

Dragon 32 native caller after accepted input.
Captured from the running caller in the configuration below.

Where setup, trigger and service belong

demo.bas
10 N=0
20 CLS:PRINT "TURN";N
21 GOSUB 1000
30 GOSUB 3000
40 IF A=1 THEN N=N+1:GOSUB 2000
50 GOTO 20
1000 PRINT "XXX"
1010 PRINT "X X"
1020 PRINT "XXX"
1030 RETURN
2000 SOUND 100,2
2010 RETURN
3000 INPUT A
3010 RETURN

Compare blocking, serviced and queued sound when choosing the next step.

Verification and sources

Target: Dragon 32 PAL, stock Extended Colour BASIC. These callers were executed with released Emu198x 0.44.1; assembly uses Asm198x 0.0.71. The sample folder contains reproduction instructions and retained observations. The independent checker binds source, native captures and actual output; its rejection tests exercise wrong state, missing files and false audio claims.

This qualifies the named emulator/firmware path. Pitch accuracy, original hardware and other peripherals require their own observations.

Dragon Data, Dragon 32 User Manual: INPUT, GOSUB/RETURN and SOUND; ROM sound generation.