EM73P461A
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
RAM
address
20H
21H
22H
:
COM3
bit3
COM2
bit2
COM1
bit1
COM0
bit0
SEG0
SEG1
SEG2
:
:
:
SEG30
SEG31
3EH
3FH
The relation between LCD display data and driving method
Driving method
1/4 duty
bit3
bit2
bit1
COM1
COM1
COM1
-
bit0
COM3
COM2
COM0
COM0
COM0
COM0
1/3 duty
-
-
-
COM2
1/2 duty
Static
-
-
LCD frame frequency : According to the drive method to set the frame frequency.
Duty
Frame frequency (Hz)
64 x (4/4) = 64
64 x (4/3) = 85
64 x (4/2) = 128
64
1/4 duty
1/3 duty
1/2 duty
Static
PROGRAM EXAMPLE :
LDIA
OUTA
LDIA
OUTA
#0001B
P27
#1001B
P27
; 1/4 duty, 1/2 bias
; enable LCD
LCD DRIVING METHODS
There are six kinds of driving methods can be selected by DUTY (P27.0~P27.2). The drivinf waveforms of
LCD driver are as below :
• VDD=3V
(1) 1/4 duty (1/3 bias)
(2 ) 1/3 duty (1/3 bias)
V
DD
V3
V2
V1
V
DD
V3
V2
V1
3V
2V
1V
3V
2V
1V
VA
VB
VA
VB
V
SS
V
SS
V3
V3
COM0
COM1
V2
V1
Vss
V2
V1
Vss
V3
V2
V1
Vss
V3
V2
V1
Vss
V3
V2
V1
Vss
V3
V2
V1
Vss
COM2
COM3
V3
V2
V1
Vss
V3
V2
V1
Vss
V3
V2
V1
Vss
SEG0
V3
V2
V1
Vss
-V1
-V2
-V3
V3
V2
V1
Vss
-V1
-V2
-V3
SEG0-COM0
ON
V3
V2
V1
Vss
-V1
-V2
-V3
V3
V2
V1
Vss
-V1
-V2
-V3
SEG0-COM1
OFF
Frame
Frame
* This specification are subject to be changed without notice.
12.27.2001
24
ELAN [ ELAN MICROELECTRONICS CORP ]
