Holtek HT66F0175 - SCOM;SSEG Function for LCD; LCD Operation

Rev. 1.50 148 August 28, 2017 Rev. 1.50 149 August 28, 2017
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
HT66F0175/HT66F0185
A/D Flash MCU with EEPROM
SCOM/SSEG Function for LCD
ThedeviceshavethecapabilityofdrivingexternalLCDpanels.Thecommonandsegmentpins
forLCDdriving,SCOM0~SCOM5andSSEG0~SSEG19orSSEG0~SSEG23,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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R-typebiascurrentontheSCOM
andSSEGpins.ThisenablestheLCDCOMandSEGdrivertogeneratethenecessaryV
SS
,(1/3)
V
DD
,(2/3)V
DD
andV
DD
voltagelevelsforLCD1/3biasoperation.
TheLCDENbitintheSLCDC0registeristheoverallmastercontrolfortheLCDdriver.Thisbitis
usedinconjunctionwiththeCOMnENandSEGnENbitstoselectwhichI/OpinsareusedforLCD
driving.NotethatthecorrespondingPortControlregisterdoesnotneedtorstsetupthepinsas
outputstoenabletheLCDdriveroperation.
V
DD
(2/3) V
DD
(1/3) V
DD
V
DD
LCD
Voltage
Select
Circuit
LCD
COM/SEG
Analog Switch
LCDEN
ISEL[1:0]
COMnEN COMSEGSn
66
SEGmEN
FRAME
SCOM0/SSEG0
SCOM5/SSEG5
SSEG6
SSEGm
m = 19 for HT66F0175
m = 23 for HT66F0185
Software Controlled LCD Driver Structure