Routines
Prev: 9E6D Up: Map Next: 9E93
9E86: Play Pulse
Used by the routines at PlayDefaultBuzz and PlayRandomNoise.
Plays one cycle of a tone, by setting the speaker bit for a time and then clearing it for a time. This is the basis of the sound effects.
Input
B The length of the pulse
D The length of the gap
PlayPulse 9E86 LD A,$10 Set the speaker bit.
9E88 OUT ($FE),A Write to the port.
PlayPulse_Pulse 9E8A DJNZ PlayPulse_Pulse Wait for the length of the pulse.
9E8C XOR A Clear the speaker bit.
9E8D OUT ($FE),A Write to the port.
9E8F LD B,D Copy the length of the gap into B.
PlayPulse_Gap 9E90 DJNZ PlayPulse_Gap Wait for the length of the gap.
9E92 RET Return.
View the equivalent code in;
Prev: 9E6D Up: Map Next: 9E93