Holtek HT66F20 - LCD Bias Control

Rev. 2.50 228 June 22, 2017 Rev. 2.50 229 June 22, 2017
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
HT66F20/HT66F30/HT66F40/HT66F50/HT66F60
HT66FU30/HT66FU40/HT66FU50/HT66FU60
A/D Flash MCU with EEPROM
LCD Bias Control
TheLCDCOMdriverenablesarangeofselectionstobeprovidedtosuittherequirementofthe
LCDpanelwhichisbeingused.ThebiasresistorchoiceisimplementedusingtheISEL1andISEL0
bitsintheSCOMCregister.
SCOMC Register
• HT66F20
Bit 7 6 5 4 3 2 1 0
Name
D7 ISEL1 ISEL0 SCOMEN COM3EN COM2EN COM1EN COM0EN
R/W R/W R/W R/W R/W R/W R/W R/W R/W
POR 0 0 0 0 0 0 0 0
Bit7 ReservedBit
0:Correctlevel-bitmustberesettozeroforcorrectoperation
1:Unpredictableoperation-bitmustnotbesethigh
Bit6~5 ISEL1, ISEL0:SelectSCOMtypicalbiascurrent(V
DD
=5V)
00:25μA
01:50μA
10:100μA
11:200μA
Bit4 SCOMEN:SCOMmoduleControl
0:Disable
1:Enable
Bit3 COM3EN:PC3orSCOM3selection
0:GPIO
1:SCOM3
Bit2 COM2EN:PC2orSCOM2selection
0:GPIO
1:SCOM2
Bit1 COM1EN:PC1orSCOM1selection
0:GPIO
1:SCOM1
Bit0 COM0EN:PC0orSCOM0selection
0:GPIO
1:SCOM0