HT1647 is a peripheral device specially designed for I/O type C used to expand the display
capability. The max. display segment of
the device are 1024 patterns (64 segments and
16 commons). It also supports four data bits interface,
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 (Electrically
Controlled Birefringence) LCDs in addition
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 the HT1647 drives a TN-type,
STN-type LCDs. It displays four color output
when the HT1647 drives an 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
subsystems. Only six lines (CS, WR,
DB0~DB3) are required for the interface between the host controller and the HT1647.