HT1621B詳細(xì)參數(shù)： 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 32x4 LCD driver Built-in 32x4 bit display RAM 3-wire serial 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 HT1621: 44-pin QFP package HT1621B: 48-pin SSOP/LQFP packages HT1621D: 28-pin SKDIP package HT1621G: Gold bumped chip