Holtek BS82B12A-3 - SCOM and SSEG Function for LCD; LCD Ope�Ation

Rev. 1.20 142 January 23, 2015 Rev. 1.20 143 January 23, 2015
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
BS82B12A-3/BS82C16A-3/BS82D20A-3
Touch Key 8-Bit Flash MCU with LED/LCD Driver
SCOM and SSEG Function for LCD
ThedeviceshavethecapabilityofdrivingexternalLCDpanels.ThecommonpinsforLCDdriving,
SCOM0~SCOM3,SSEG0~SSEG19,arepinsharedwithcertainpinsontheI/Oports.TheLCD
signals(COMandSEG)aregeneratedusingtheapplicationprogram.
LCD Operation
AnexternalLCDpanelcanbedrivenusingthedevicesbyconguringtheI/Opinsascommonpins
andconguringtheI/Opinsassegmentpins.TheLCDdriverfunctioniscontrolledusingtheLCD
controlregisterswhichinadditiontocontrollingtheoverallon/offfunctionalsocontrolstheSCOM
andSSEGoperatingcurrent.ThisenablestheLCDCOMandSEGdrivertogeneratethenecessary
V
SS
,(1/3)V
DD
,(2/3)V
DD
voltageandV
DD
levelsforLCD1/3biasoperation.
TheLCDENbitintheSLCDC0registeristheoverallmastercontrolfortheLCDdriver,however
thisbitisusedinconjunctionwiththeCOMnENandSEGnENbitstoselectwhichI/OPortpins
areusedforLCDdriving.NotethatthePortControlregisterdoesnotneedtorstsetupthepinsas
outputstoenabletheLCDdriveroperation.
LCD Driver Structure