W681307DG Datasheet, PDF (48/160 Pages) Winbond – USB1.1 CODEC Microprocessor Control Unit with 32KB Mask ROM and 4KB RAM.

W681307
8.4
PIEZO Tone Generator
8.4.1
Overview
The PIEZO signal can generated by the Ringer Tone generator, this subsection describe the PIEZO-driving clock from the Ringer tone
generator, shown in Figure 8-4.
8.4.2
Functionality
VCC
PCM1/RT0
INDUCTOR
R
DIODE
C
R
Piezo
R
SNDR
Figure 8-4 Piezo tone circuit
The PCM1/RTO pin generates the driving signal to obtain higher voltage. When set register 0x144B[0], will enable the functionality of
Piezo, 0x144B[1] select the frequency of 108KHz or 216KHz for driving signal. The register 0x144C[7:0] output the twice number of
clock for up conversion the voltage. The Soundertone and SounderVol register controls the melody of piezo.
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Publication Release Date: May, 2007
Revision 1.3