EM73P362
4-BIT MICRO-CONTROLLER FOR LCD PRODUCT
LCD DRIVER
EM73P362 can directly drive the liquid crystal display (LCD) and has 27 segment, 3 common output pins.
There are total 27 x 3 dots can be display. The VDD, VEE, VA, VB and VSS pins are the bias voltage
inputs of the LCD driver. The method of LCD programming is RAM mapping.
CONTROL OF LCD DRIVER
The LCD driver control command register is P27. When LDC is 00, the LCD is disabled and changes the
duty only. When LDC is 01, the LCD is blanking, the COM pins are inactive and the SEG pins continuously
output the display data. When LDC is 11, the LCD driver enables, the power switch is turned on and it
cannot be turned off forever except the CPU is reseted or in the STOP operation mode. Users must enable
the LCD driver by self when the CPU is woke up.
P27
3
2
1
0
Initial value : 0000
LDC
DUTY
LDC LCD display control
0 0 LCD display disable
0 1 Blanking
1 0 Reserved
1 1 LCD display enable
DUTY
0 0
0 1
1 0
1 1
Driving method select
Reserved
1/3 duty ( 1/2 bias )
1/2 duty ( 1/2 bias )
Static
LCD driving methods
There are four kinds of driving methods can be selected by DUTY ( P27.0 ~ P27.1 ). The driving wave
forms of LCD driver are as below :
1/3 duty (1/2 bias)
1/2 duty (1/2 bias)
Static
C
O
M
0
C
O
M
1
C
O
M
2
COM0
COM1
COM2
SEG0
SEG0
SEG1
SEG2
:
ON OFF
SEG0 - COM0
ON
SEG0 - COM1
OFF
Frame
Frame
Frame
* This specification are subject to be changed without notice.
11.1.2001
19
ELAN [ ELAN MICROELECTRONICS CORP ]
