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5.12 Sound Generator
5.12.1 Configuration of sound generator
The E0C88832/88862 has a built-in sound generator
for generating the buzzer (BZ and BZ) signal.
The BZ signal generated from the sound generator
can be output from the R50 output port terminal.
Furthermore, the R51 terminal can be set as the BZ
signal (BZ inverted signal) output by mask option.
Aside permitting the respective setting of the
buzzer signal frequency and sound level (duty
adjustment) to 8 stages, it permits the adding of a
digital envelope by means of duty ratio control. It
also has a one-shot output function for outputting
key operated sounds.
Figure 5.12.1.1 shows the configuration of the
sound generator.
BZFQ0–BZFQ2
f
OSC1
OSC1
Programmable
oscillation circuit
dividing circuit
ENRST
256 Hz
Dividing circuit
addition circuit
One-shot buzzer
control circuit
BZSTP
Fig. 5.12.1.1 Configuration of sound generator
E0C88832/88862 TECHNICAL MANUAL
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Sound Generator)
ENRTM
Envelope
Duty ratio
control circuit
ENON
BZSHT
Buzzer output
control circuit
SHTPW
BZON
Register BZSHT
Register BZSTP
Register BZON
5.12.2 Control of buzzer output
The BZ signal can be output from the R50 output
port terminal. Furthermore, the R51 output port
terminal can be used to output the BZ signal (BZ
inverted signal) by mask option.
The configuration of the output ports R50 and R51
is shown in Figure 5.12.2.1.
The output control for the buzzer signal generated by
the sound generator is done by the buzzer output
control register BZON, one-shot buzzer trigger bit
BZSHT and one-shot buzzer forced stop bit BZSTP.
When "1" is set to BZON or BZSTP, the R50 goes
LOW (V
) and the R51 goes HIGH (V
SS
To output the buzzer signal, "0" must always be set
for the data register R50D. The data register R51D
does not affect the BZ output.
Figure 5.12.2.2 shows the output waveform of the
buzzer signal.
Note: Since the buzzer signal is generated asyn-
chronously from the registers BZON, BZSHT
and BZSTP, when the signal is turned ON or
OFF by the register settings, a hazard of a 1/
2 cycle or less is generated.
DUTY0–DUTY2
Output port
R50, R51
∗
Available when selected
by mask option
Register R50D
BZ signal
S
Q
One-shot
R
time up
Register R51D
Fig. 5.12.2.1 Configuration of R50 and R51
BZON/BZSHT
BZ output (R50)
BZ output (R51) *
Fig. 5.12.2.2 Buzzer output waveform
EPSON
).
DD
BZ (R50)
BZ (R51)*
Mask option
0
1
∗ when selected by mask option
R50 output
R51 output
103
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