FS9912

Rev. 3.6

22/34

11.2 Power System

Address

Name

Content

02CH

NETD

PUMPEN

LBCEN

BNDEN

LCDEN

REGEN

GNDEN

BIASEN

02DH

SVD

LB

Voltage

Doubler

Voltage

Regulator

LCD

Bias

Bandgap

Voltage

Reference

Analog

Common

Generator

Bias

Circuit

CB

CA

VGG

AGND

VB

Low Battery

Compararor

VDD

VSS

REGEN

BIASEN

Bias(to Analog Circuit)

GNDEN

PUMPEN

Pump Clock

LCDEN

VC3,VC2,VC1

(To LCD Driver)

BNDEN

LBCEN

LB

1uF

1uF

1uF

1uF

100k

1uF

10nF

100k

GNDEN=1 will start the internal analog common generator circuit, and the AGND voltage is about (vdd,

vss)/2.

PUMPEN=1 will start the voltage doubler circuit. VGG voltage is about 2VDD.

PMPS (PT2MR [0]) will set the voltage doubler operation frequency: 0 is 2.7kHz, and 1 is 10kHz.

REGEN=1 will start the internal voltage regulator. VDDA voltage is about 4V.

LCDEN=1 will start the LCD driver bias circuit. The LCD bias voltages are RLCD, 2/3RLCD, 1/3RLCD,

and vss respectively.

BNDEN=1 will start the internal bandgap voltage reference. The output voltage (REFO, AGND) is about

1.2V.

LBCEN=1 will start the low battery check comparator. The comparator inputs are VDD and REFO

respectively, and the low battery check voltage is about 2.4V.

11.3 I/O Port

11.3.1 I/O Port1(PT1)

Address

Name

Content

020H

PT1

PT1 [7:0]

021H

PT1EN

PT1EN [7:0]

022H

PT1PU

PT1PU [7:0]

023H

PT1MR

E1M1

E1M0

E0M1

E0M0