HT1647

General Description

       HT1647 is a peripheral device specially designed for I/O type MCU 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. 

Features

• Operating voltage: 2.7V~5.2V
• Built-in 32kHz RC oscillator
• External 32.768kHz crystal oscillator or 32kHz frequency source input
• Standby current: <1uA at 3V, <2uA at 5V
• Internal resistor type: 1/5 bias or
  1/4 bias, 1/16 duty
• Two selectable LCD frame
  frequencies: 89Hz or 170Hz
• Max. 64x16 patterns, 64 segments and 16 commons
• Built-in bit-map display RAM: 2048 bits (=64x16x2 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
• 100-pin QFP and in chip form