ht1621HT1621 RAM Mapping 324 LCD Controller for I/O mC 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 ……