Lcd Bias Control - Holtek HT66F20 Manual

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
Name D�
R/W R/W
POR 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
ISEL1, ISEL0: Select SCOM typical bias current (V
Bit 6~5
00: 25μA
01: 50μA
10: 100μA
11: 200μA
SCOMEN: SCOM module Control
Bit 4
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
Rev. 2.50
6 5 4
ISEL� ISEL0 SCOMEN COM3EN
R/W R/W R/W
0 0 0
229
3 2 1
COM2EN COM�EN
R/W R/W R/W
0 0 0
=5V)
DD
0
COM0EN
R/W
0
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