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Routines |
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Plays a single cycle of a square wave: the speaker is turned on for the duration and then off for the same duration.
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| PlaySquareWave | 49012 | LD A,16 | A=16 (bit 4 turns the speaker on). | |||||
| 49014 | OUT (254),A | Write A to port 254 (border black, speaker on). | ||||||
| 49016 | LD A,B | Stash the duration in A. | ||||||
| PlaySquareWave_Loop | 49017 | DJNZ PlaySquareWave_Loop | Decrease duration by one and loop back to PlaySquareWave_Loop until it is zero. | |||||
| 49019 | LD B,A | Restore the duration to B. | ||||||
| 49020 | XOR A | A=0. | ||||||
| 49021 | OUT (254),A | Write A to port 254 (border black, speaker off). | ||||||
| 49023 | LD A,B | Stash the duration in A. | ||||||
| Silence_Loop | 49024 | DJNZ Silence_Loop | Decrease duration by one and loop back to Silence_Loop until it is zero. | |||||
| 49026 | LD B,A | Restore the duration to B. | ||||||
| 49027 | RET | Return. | ||||||
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View the equivalent code in;
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