SIC63616-(Rev. 1.0) NO. P135
3240-0412
4.11 Sound Generator
4.11.1 Configuration of sound generator
The S1C63616 has a built-in sound generator for generating a buzzer signal.
Hence, the generated buzzer signal can be output from the BZ terminal.
Aside permitting the respective setting of the buzzer signal frequency and sound level 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 4.11.1.1 shows the configuration of the sound generator.
f
OSC1
f
OSC1
/128
SGCKE
Clock
manager
P03(BZ) terminal
Programmable
dividing circuit
One-shot buzzer
control circuit
Duty ratio
control circuit
BZFQ0–BZFQ2
BDTY0–BDTY2
Buzzer output
control circuit
Envelope
addition circuit
ENON
BZE
ENRTM
ENRST
BZSTP
BZSHT
SHTPW
Fig. 4.11.1.1 Configuration of sound generator
Note: If the BZ terminal is used to drive an external component that consumes a large amount of current
such as a bipolar transistor, design the pattern of traces on the printed circuit board so that
the operation of the external component does not affect the IC power supply. Refer to <Output
Terminals> in Section 5.3, "Precautions on Mounting", for more information.
4.11.2 Controlling clock manager
To generate the buzzer signal, the clock for the sound generator must be supplied from the clock manager
by writing "1" to the SGCKE register in advance.
Table 4.11.2.1 Controlling sound generator clock
SGCKE
1
0
Sound generator clock
Programmable dividing circuit input clock: f
OSC1
(32 kHz)
One-shot buzzer control circuit input clock: f
OSC1
/ 128 (256 Hz)
Off
If it is not necessary to run the sound generator, stop the clock supply by setting SGCKE to "0" to reduce
current consumption.
4.11.3 Control of buzzer output
The BZ signal generated by the sound generator is output from the P03 (BZ) terminal by setting "1" for
the buzzer output enable register BZE. The I/O control register IOC03 and data register P03 settings are
ineffective while the BZ signal is being output.
When BZE is set to "0", the P03 port is configured as a general-purpose DC input/output port.
BZE register
BZ output (P03 terminal)
"1"
"0"
"0"
Fig. 4.11.3.1 Buzzer signal output timing chart
Note: Since it generates the buzzer signal that is out of synchronization with the BZE register, hazards may
at times be produced when the signal goes on/off due to the setting of the BZE register.