序列化HD44780的液晶显示器

摘要：除了减少所需的GPIO线从十一点到两个数量，该电路还提供了可编程的对比度和背光控制。

Maxim>AppNotes>DisplayDriversKeywords:LCDdriver,opamp,I/Oportexpander,contrastcontrol,backlight-intensitycontrol,digital-to-Nov23,2005analogconverter,DACAPPLICATIONNOTE3658SerializinganHD44780LCDDisplayAbstract:BesidesreducingthenumberofrequiredGPIOlinesfromeleventotwo,thiscircuitalsoprovidesprogrammablecontrastandbacklightcontrol.MostLCDcharacterdisplaysconnecttotheoutsideworldthroughacontrollerIC,suchastheHD44780(Hitachi)orequivalent.Thatinterfacehasseriousdrawbacks,however.Itusesupalargenumberofthemicrocontroller'sgeneral-purposeinput/output(GPIO)pins,anditisn'tcapableofprovidingdigital-contrastorbacklight-intensitycontrol.ThecircuitinFigure1reducestherequirednumbero