S1C63358 TECHNICAL MANUAL
EPSON
101
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Buzzer Output Circuit)
4.13 Buzzer Output Circuit
4.13.1 Configuration of buzzer output circuit
The S1C63358 is capable of generating buzzer signal to drive a piezo-electric buzzer. The buzzer signal is
output from the BZ terminal by software control. Furthermore, the buzzer signal frequency can be set to 2
kHz or 4 kHz with 2 Hz interval by software.
Figure 4.13.1.1 shows the configuration of the buzzer output circuit.
f
OSC1
BZ
2 kHz
4 kHz
Selector
Buzzer output
control circuit
BZON
BZFQ
Divider
ENON
Fig. 4.13.1.1 Configuration of buzzer output circuit
4.13.2 Mask option
Polarity of the buzzer signal output from the BZ terminal can be selected as either positive polarity or
negative polarity. Figure 4.13.2.1 shows each output circuit configuration and the output waveform.
When positive polarity is selected, the BZ terminal goes to a low (V
SS
) level when the buzzer signal is not
output. Select positive polarity when driving a piezo buzzer by externally connecting an NPN transistor.
When negative polarity is selected, the BZ terminal goes to a high (V
DD
) level when the buzzer signal is not
output. Select negative polarity when driving a piezo buzzer by externally connecting a PNP transistor.
V
DD
V
SS
Buzzer signal
BZ
V
SS
V
DD
Piezo
(a) When positive polarity is selected
V
DD
V
SS
Buzzer signal
BZ
V
SS
V
DD
Piezo
(b) When negative polarity is selected
Fig. 4.13.2.1 Configuration of output circuit
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