HT1647
4-Level Gray Scale 6416 LCD Controller for I/O mC
1
April 21, 2000
Features
Operating voltage: 2.7V~5.2V
Built-in 32kHz RC oscillator
External 32.768kHz crystal oscillator or
32kHz frequency source input
Standby current < 1mA at 3V, < 2mA at 5V
Internal resistor type: 1/5 bias or 1/4
bias, 1/16 duty
Two selectable LCD frame frequencies:
89Hz or 170Hz
Max. 6416 patterns, 64 segments and 16
commons
Built-in bit-map display RAM: 2048 bits
(=64162 bits)
Built-in internal resistor type bias generator
Six-wire interface (four data wires)
Eight kinds of time base/WDT selection
Time base or WDT overflow output
R/W address auto increment
Built-in buzzer driver (2kHz/4kHz)
Power down command reduces power
consumption
Software configuration feature
Data mode and Command mode
instructions
Three data accessing modes
Provides VLCD pin to adjust LCD operating
voltage
Provides three kinds of bias current
programming
Control of TN-type, STN-type LCDs and
ECB-type LCDs
Four-level gray scale output for TN-type,
STN-type LCDs panel
Four-color output for ECB-type LCDs panel
Available in 100-pin QFP and in chip form
General Description
HT1647 is a peripheral device specially de-
signed for I/O type mC used to expand the dis-
play capability. The max. display segment of
the device are 1024 patterns (64 segments and
16 commons). It also supports four data bits in-
terface, buzzer sound, Watchdog Timer or time
base timer functions. The HT1647 is a memory
mapping and multi-function LCD controller.
Since the HT1647 can control ECB-type (Elec-
trically Controlled Birefringence) LCDs in ad-
dition to current TN-type (Twisted Nematic) or
STN-type (Super Twisted Nematic) LCDs, it
can support 4-color display as well as 4-level
gray scale display. It displays 4-level gray scale
output when HT1647 drives TN-type,
STN-type LCDs. It displays four color output
when HT1647 drives ECB-type. HT1647 uses
PWM (Pulse Width Modulation) technique. The
software configuration feature of the HT1647
make it suitable for multiple LCD applications
including LCD modules and display subsys-
tems. Only six lines (CS, WR, DB0~DB3) are
required for the interface between the host con-
troller and the HT1647. The HT164X series
have many kinds of products that match vari-
ous applications.
Applications
Toys
Games
Personal digital assistant
Cellular phone
Global positioning system
Consumer electronics
4-Level Gray Scale LCD Controller Product Line Selection Table
HT164X
*HT1642
*HT1645
HT1647
COM
8
8
16
SEG
32
64
64
*Under development
Block Diagram
HT1647
2
April 21, 2000
W a t c h d o g T i m e r
&
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
&
T i m i n g
C i r c u i t
W R
O S C I
C S
R D
C O M 0
C O M 1 5
S E G 0
S E G 6 3
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
O S C O
D B 0
D B 3
N o t e : C S : C h i p s e l e c t i o n
B Z , B Z : T o n e o u t p u t s
W R , R D : W R I T E c l o c k , R E A D c l o c k
D B 0 ~ D B 3 : D a t a b u s
C O M 0 ~ C O M 1 5 , S E G 0 ~ S E G 6 3 : L C D o u t p u t s
I R Q : T i m e b a s e o r W D T o v e r f l o w o u t p u t
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