ACT apricot - Page 192

SOUND GENERATION
Reference selection
NFl NFO
Reference
0 0
3.90 kHz
0
1
1. 95 kHz
1 0
975 Hz.
1 1
Tone Generator
Mode selection
FB
Mode
0
"Periodic noise"
1 "White noise"
The level of the noise signal is determined by a level
control
byte which allows a choice of 15 different levels of
noise signal
to be set, and also enables the noise generator to
be switched off. The format of the level control byte is
identical
to the format of the level control byte described in
the tone generator section above. The only difference
between the level control bytes for a tone generator and the
noise generator is the register selection bits.
NOTE: The noise generator is normally assigned to produce
a keyclick, each
time a key is pressed by updating both the
noise generator register and the noise attenuator register.