EM73P361A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
the COM pins are inactive and the SEG pins continously output the display data. When LDC is 11, the LCD
driver enables, the power swich is turned on and it cannot be turned off forever except the CPU is reseted or
sleeping. Users must enable the LCD driver by self when the CPU is waked up.
Port27
3
2
1
0
Initial value : 0000
LDC
DUTY
LDC
LCD display control
LCD display disable & change duty
Blanking
Reserved
LCD display enable
DUTY
Driving method select
Reserved
1/3 duty (1/2 bias)
1/2 duty (1/2 bias)
Static
0
0
1
1
0
0
0
1
1
0
1
0
1
1
0
1
LCD driving methods
There are four kinds of driving methods can be selected by DUTY (P27.0~P27.1). The driving waveforms of
LCD driver are as below :
1/3 duty (1/2 bias)
1/2duty (1/2 bias)
Static
C
O
M
0
C
O
M
1
C
O
M
2
COM0
COM1
SEG0
SEG1
COM2
SEG0
OFF
ON
SEG2
:
SEG0-COM0
ON
SEG0-COM1
OFF
Frame
Frame
Frame
LCD Frame frequency : According to the drive method to set the frame frequency.
Driving method
1/3 duty
Frame frequency (Hz)
43 x (3/3) = 43
43 x (3/2) = 64
43
1/2 duty
Static
The relation between LCD display data and driving method
Driving method
1/3 duty
bit3
bit2
COM2
bit1
COM1
COM1
-
bit0
-
-
-
COM0
COM0
COM0
1/2 duty
Static
-
-
LCD drive voltage
EM73P361A provides 2 kinds of LCD bias methods, capacitor divider and resistor divider, when the LCD bias
method is capacitor divider,the VA is connected a capacitor to VB and the VEE is connected a capacitor
to VSS. The output of VEE is 1.5V for LCD bias voltage. When the LCD bias method is resistor divider, the
VEE is floating.
* This specification are subject to be changed without notice.
12.17.2001
18
ELAN [ ELAN MICROELECTRONICS CORP ]
