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Merge pull request #204 from lynchaj/patch-5

Create tone3.asm
pull/207/head
Wayne Warthen 5 years ago
committed by GitHub
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  1. 35
      Source/Apps/tone3.asm

35
Source/Apps/tone3.asm

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; program to test user buzzer/speaker on Z80 MBC clock board
; by Andrew Lynch, 6 Jul 2021
org $0100
LD HL,$7FFF ; INITIALIZE OUTER LOOP
LD DE,$0001 ; DECREMENT VALUE
START:
LD A,%00000100
OUT ($70),A ; TURN ON SPEAKER
LD B,$80 ; HOLD SPEAKER ON FOR 128 COUNTS
LOOP1: DJNZ LOOP1
LD A,%00000000
OUT ($70),A ; TURN OFF SPEAKER
LD B,$80 ; HOLD SPEAKER OFF FOR 128 COUNTS
LOOP2: DJNZ LOOP2
SBC HL,DE ; REDUCE OUTER LOOP BY 1
JR NZ,START ; LOOP 32768 TIMES, ABOUT 15 SECONDS
LD A,%00000011
OUT ($70),A ; TURN ON BOTH USER LEDS
; HALT ; HALT & TURN ON HALT LED
RET
end
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