HT1621
RAM Mapping 324 LCD Controller for I/O mC
Selection Table
HT162X
HT1620
HT1621
HT1622
HT16220
HT1623
HT1625 HT1626
COM
4
4
8
8
8
8
16
SEG
32
32
32
32
48
64
48
Built-in Osc.
Crystal Osc.
1
January 10, 2001
Features
Operating voltage : 2.4V~5.2V
Built-in 256kHz RC oscillator
External 32.768kHz crystal or 256kHz
frequency source input
Selection of 1/2 or 1/3 bias, and selection of
1/2 or 1/3 or 1/4 duty LCD applications
Internal time base frequency sources
Two selectable buzzer frequencies
(2kHz/4kHz)
Power down command reduces power
consumption
Built-in time base generator and WDT
Time base or WDT overflow output
8 kinds of time base/WDT clock sources
324 LCD driver
Built-in 324 bit display RAM
3-wire serial interface
Internal LCD driving frequency source
Software configuration feature
Data mode and command mode
instructions
R/W address auto increment
Three data accessing modes
VLCD pin for adjusting LCD operating
voltage
General Description
The HT1621 is a 128 pattern (324), memory
mapping, and multi-function LCD driver. The
S/W configuration feature of the HT1621
makes it suitable for multiple LCD applica-
tions including LCD modules and display sub-
systems. Only three or four lines are required
for the interface between the host controller
and the HT1621. The HT1621 contains a power
down command to reduce power consumption.
Block Diagram
Note: 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
HT1621
2
January 10, 2001
W a t c h d o g T i m e r
a n d
T i m e B a s e G e n e r a t o r
D i s p l a y R A M
L C D D r i v e r /
B i a s C i r c u i t
C o n t r o l
a n d
T i m i n g
C i r c u i t
D A T A
W R
O S C O
O S C I
C S
R D
C O M 0
C O M 3
S E G 0
S E G 3 1
T o n e F r e q u e n c y
G e n e r a t o r
B Z
B Z
I R Q
V S S
V D D
V L C D
Pin Assignment
HT1621
3
January 10, 2001
S E G 7
S E G 6
S E G 5
S E G 4
S E G 3
S E G 2
S E G 1
S E G 0
C S
R D
W R
D A T A
V S S
O S C O
N C
O S C I
V D D / V L C D
I R Q
B Z
B Z
C O M 0
C O M 1
C O M 2
C O M 3
S E G 8
S E G 9
S E G 1 0
S E G 1 1
S E G 1 2
S E G 1 3
S E G 1 4
S E G 1 5
S E G 1 6
S E G 1 7
S E G 1 8
S E G 1 9
S E G 2 0
S E G 2 1
S E G 2 2
S E G 2 3
S E G 2 4
S E G 2 5
S E G 2 6
S E G 2 7
S E G 2 8
S E G 2 9
S E G 3 0
S E G 3 1
H T 1 6 2 1
4 8 S S O P
S E G 7
S E G 6
S E G 5
S E G 4
S E G 3
S E G 2
S E G 1
S E G 0
C S
R D
W R
D A T A
V S S
O S C O
O S C I
V L C D
V D D
I R Q
B Z
B Z
C O M 0
C O M 1
C O M 2
C O M 3
S E G 8
S E G 9
S E G 1 0
S E G 1 1
S E G 1 2
S E G 1 3
S E G 1 4
S E G 1 5
S E G 1 6
S E G 1 7
S E G 1 8
S E G 1 9
S E G 2 0
S E G 2 1
S E G 2 2
S E G 2 3
S E G 2 4
S E G 2 5
S E G 2 6
S E G 2 7
S E G 2 8
S E G 2 9
S E G 3 0
S E G 3 1
H T 1 6 2 1 B
4 8 S S O P / D I P
4 8
4 7
4 6
4 5
4 4
4 3
4 2
4 1
4 0
3 9
3 8
3 7
3 6
3 5
3 4
3 3
3 2
3 1
3 0
2 9
2 8
2 7
2 6
2 5
1
2
3
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
2 0
2 1
2 2
2 3
2 4
4 8
4 7
4 6
4 5
4 4
4 3
4 2
4 1
4 0
3 9
3 8
3 7
3 6
3 5
3 4
3 3
3 2
3 1
3 0
2 9
2 8
2 7
2 6
2 5
1
2
3
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
2 0
2 1
2 2
2 3
2 4
S E G 5
S E G 3
S E G 1
C S
R D
W R
D A T A
V S S
V L C D
V D D
I R Q
B Z
C O M 0
C O M 1
H T 1 6 2 1 D
2 8 S K D I P
S E G 7
S E G 9
S E G 1 1
S E G 1 3
S E G 1 5
S E G 1 7
S E G 1 9
S E G 2 1
S E G 2 3
S E G 2 5
S E G 2 7
S E G 2 9
S E G 3 1
C O M 2
2 8
2 7
2 6
2 5
2 4
2 3
2 2
2 1
2 0
1 9
1 8
1 7
1 6
1 5
1
2
3
4
5
6
7
8
9
1 0
1 1
1 2
1 3
1 4
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