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ManualsBrandsMICROCHIP TECHNOLOGY ManualsMicrocontrollers, Microprocessors & QuartzesEmbedded microcontroller TQFP 64 (14x14) 8-Bit 20 MHz I/O number 54
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241
8284D–AVR–6/11
ATmega169A/PA/329A/PA/3290A/PA/649A/P/6490A/P
Figure 24-4. Driving a LCD with Two Common Terminals
24.3.3 1/3 Duty and 1/3 Bias
1/3 bias is usually recommended for LCD with three common terminals (1/3 duty). Waveform is
shown in Figure 24-5. SEG0 - COM0 is the voltage across a segment that is on and SEG0-
COM1 is the voltage across a segment that is off.
Figure 24-5. Driving a LCD with Three Common Terminals
24.3.4 1/4 Duty and 1/3 Bias
1/3 bias is optimal for LCD displays with four common terminals (1/4 duty). Waveform is shown
in Figure 24-6 on page 242. SEG0 - COM0 is the voltage across a segment that is on and SEG0
- COM1 is the voltage across a segment that is off.
V
LCD
GND
V
LCD
1
/
2
V
LCD
GND
V
LCD
1
/
2
V
LCD
GND
-1
/
2
V
LCD
-V
LCD
SEG0
COM0
SEG0 - COM0
Frame Frame
V
LCD
GND
V
LCD
1
/
2
V
LCD
GND
V
LCD
1
/
2
V
LCD
GND
-1
/
2
V
LCD
-V
LCD
SEG0
COM1
SEG0 - COM1
Frame Frame
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
-
1
/
3
V
LCD
-
2
/
3
V
LCD
-V
LCD
SEG0
COM0
SEG0 - COM0
Frame Frame
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
V
LCD
2
/
3
V
LCD
1
/
3
V
LCD
GND
-
1
/
3
V
LCD
-
2
/
3
V
LCD
-V
LCD
SEG0
COM1
SEG0 - COM1
Frame Frame