Files
RomWBW/Source/Apps/MBC/tone3.asm
Wayne Warthen 7416f5f79e Test Apps
- Converted tstdskng to TASM and added to build scripts.
- Moved MBC specific test apps to their own directory.
2021-07-06 18:45:40 -07:00

36 lines
603 B
NASM

; 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