3 control of buzzer output – Epson S1C63558 User Manual

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S1C63558 TECHNICAL MANUAL

EPSON

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CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Sound Generator)

4.12.3 Control of buzzer output

The R01 and R00 terminals for buzzer output are set as general-purpose output ports at initial reset.
Therefore, the R01 terminal must be set as the BZ output terminal by writing "1" to the BZOUT register
before controlling buzzer output. Furthermore, the data register R01 for the R01 output port should be
fixed at "1" and the high-impedance register R01HIZ at "0".
When direct driving a piezoelectric buzzer, the R00 terminal must be set as the XBZ output terminal
similar to the R01 terminal. Write "1" to the XBZOUT register to set the XBZ output. Also in this case, the
data register R00 for the R00 output port should be fixed at "1" and the high-impedance register R00HIZ
at "0".
The buzzer signals generated by the sound generator are output from the BZ (R01) and XBZ (R00)
terminals by writing "1" to the buzzer output enable register BZE. When "0" is written to the BZE register,
the BZ (R01) terminal goes High (V

) and XBZ (R00) terminal goes Low (V

R01HIZ register

R00HIZ register

R01 register

R00 register

BZOUT register

XBZOUT register

BZE register

R01(BZ) port

R00(XBZ) port

"0"

"1"

"0"

Fig. 4.12.3.1 Buzzer signal output timing chart

Note: Since the BZ and XBZ signals are generated asynchronous to the BZE register, hazards may be

produced when the signal goes ON/OFF due to the setting of the BZE register.