ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 213

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

1/2 Duty and 1/2 Bias
2514P–AVR–07/06
Figure 99. Driving a LCD with One Common Terminal
For LCD with two common terminals (1/2 duty) a more complex waveform must be used
to individually control segments. Although 1/3 bias can be selected 1/2 bias is most
common for these displays. Waveform is shown in Figure 100. SEG0 - COM0 is the volt-
age across a segment that is on, and SEG0 - COM1 is the voltage across a segment
that is off.
Figure 100. Driving a LCD with Two Common Terminals
-1
1
1
V
GND
V
GND
V
GND
-V
/
/
/
LCD
LCD
LCD
2
2
2
-V
LCD
V
GND
V
V
GND
V
V
GND
V
LCD
LCD
LCD
LCD
LCD
LCD
LCD
Frame
Frame
Frame
Frame
SEG0
COM0
SEG0 - COM0
SEG0
COM0
SEG0 - COM0
-1
1
1
V
GND
V
GND
GND
/
/
/
2
2
2
-V
LCD
LCD
V
V
V
V
V
V
GND
GND
GND
LCD
LCD
LCD
LCD
LCD
LCD
LCD
Frame
Frame
ATmega169/V
Frame
Frame
SEG1
COM0
SEG1 - COM0
SEG0
COM1
SEG0 - COM1
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