em78p811 ELAN Microelectronics Corp, em78p811 Datasheet - Page 29

• Manufacturer Part Number: em78p811
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

VII.11.3 LCD COM and SEG signal
* COM signal : The number of COM pins varies according to the duty cycle used, as following: in 1/8 duty mode COM8
~ COM15 must be open. in 1/16 duty mode COM0 ~ COM15 pins must be used.
x:open,o:select
* SEG signal: The 60 segment signal pins are connected to the corresponding display RAM address 00h to 3Bh. The high
byte and the low byte bit7 down to bit0 are correlated to COM15 to COM0 respectively .
When a bit of display RAM is 1, a select signal is sent to the corresponding segment pin, and when the bit is 0 , a non-
select signal is sent to the corresponding segment pin.
*COM, SEG and Select/Non-select signal is shown as following:
VII.11.4 LCD Bias control
_________________________________________________________________________________________________________________________________________________________________
* This specification is subject to be changed without notice.
1/16
IOCE (Bias Control Register)
*IOCC(LCD Display data) : Bit 0 ~ Bit 8 are LCD data.
1/8
* Bit 2~4 (Bias1~Bias3) Control bits used to choose LCD operation voltage . The circuit can refer ti figure15.
* Bit 5~7 unused
Bit 0 ~ Bit 6 select LCD Display RAM address up to 120.
LCD RAM can be write whether in enable or disable mode and read only in disable mode.
-
7
COM0 COM1 COM2 COM3 COM4 COM5 COM6 COM7 COM8
o
o
LCD operate voltage
LCDA6 LCDA5 LCDA4 LCDA3 LCDA2
000
001
010
011
100
101
110
111
6
o
o
5
o
o
Bias3
Vop (VDD 5V)
4
o
o
Fig.20 Lcd wave 1/4 bias , 1/16 duty
Fig.19 Lcd wave 1/4 bias , 1/8 duty
Bias2
0.60VDD
0.66VDD
0.74VDD
0.82VDD
0.87VDD
0.93VDD
0.96VDD
1.00VDD
3
Refer to EM78811 spec.
Refer to EM78811 spec.
Refer to EM78811 spec.
Fig.21 LCD bias circuit
o
o
Bias1
2
o
o
28
1
o
o
VDD=5V
LCDA1
0
3.0V
3.3V
3.7V
4.0V
4.4V
4.7V
4.8V
5.0V
o
o
LCDA0
x
o
8-bit OTP Micro-controller
..
..
..
COM15
x
o
EM78P811