HT46R068B/HT46R069B
Enhanced A/D Type 8-bit OTP MCU
LCD SCOM Function
The devices have the capability of driving external LCD panels. The common pins for LCD
driving, SCOM0~SCOM3, are pin shared with the PB0~ PB3 pins. The LCD signals, COM and
SEG, are generated using the application program.
LCD Operation
An external LCD panel can be driven using this device by configuring the PB0~PB3 pins as
common pins and using other output ports lines as segment pins. The LCD driver function is
controlled using the SCOMC register which in addition to controlling the overall on/off function
also controls the bias voltage setup function. This enables the LCD COM driver to generate the
necessaryVDD/2 voltage levels for LCD 1/2 bias operation. The SCOMEN bit in the SCOMC
register is the overall master control for the LCD Driver, however this bit is used in conjunction
with the COMnEN bits to select which Port B pins are used for LCD driving. Note that the Port
Control register does not need to first setup the pins as outputs to enable the LCD driver operation.
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SCOM Circuit
SCOMEN
COMnEN
Pin Function
I/O
I/O
SCOMN
O/P Level
0 oꢁ 1
0 oꢁ 1
0
1
1
X
0
1
VDD/ꢃ
Output Control
Rev. 1.00
78
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HOLTEK [ HOLTEK SEMICONDUCTOR INC ]
