Block Diagram

Notes: CS: Chip selection

BZ, BZ: Tone outputs

WR,RD, DATA: Serial interface

COM0~COM3, SEG0~SEG31: LCD outputs

IRQ: Time base or WDT overflow output

VO15N: Half voltage circuit output pin

VEE: Double voltage circuit output pin

CC1/CC2: External capacitor pin, for double voltage and half voltage circuit use

HT1620

2

July 26, 1999

W a t c hd og T i m e r

&

T i m e B as e G e n e r a t o r

D i sp l a y R A M

LC D D r i v er /

Bi a s C i r c u i t

C ont r o l

and

Ti m i n g

Ci r c u i t

DA T A

WR

OSC O

OSC I

CS

RD

COM 0

COM 3

SE G 0

SE G 3 1

T o ne F r equen c y

G ene r a t o r

BZ

BZ

IR Q

VS S

VD D

CC2

CC1

V O15N

VE E