ATMEGA3290P-20AUR Atmel, ATMEGA3290P-20AUR Datasheet - Page 234

• Manufacturer Part Number: ATMEGA3290P-20AUR
• Description: MCU AVR 32K FLASH 20MHZ 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA3290P-20AUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, LCD, POR, PWM, WDT
• Number Of I /o: 69
• Program Memory Size: 32KB (16K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 1K x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

23.3.3
23.3.4
8021G–AVR–03/11
1/3 Duty and 1/3 Bias
1/4 Duty and 1/3 Bias
Figure 23-4. Driving a LCD with Two Common Terminals
1/3 bias is usually recommended for LCD with three common terminals (1/3 duty). Waveform is
shown in
COM1 is the voltage across a segment that is off.
Figure 23-5. Driving a LCD with Three Common Terminals
1/3 bias is optimal for LCD displays with four common terminals (1/4 duty). Waveform is shown
in
the voltage across a segment that is off.
Figure
-
-
2
1
2
1
2
1
1
2
-1
1
1
/
/
/
/
/
/
/
/
3
3
3
3
3
3
3
3
-V
/
/
/
V
V
V
GND
V
V
V
GND
V
V
V
GND
V
V
2
2
2
-V
V
V
V
V
V
V
GND
GND
GND
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
23-6. SEG0 - COM0 is the voltage across a segment that is on and SEG0 - COM1 is
Figure
LCD
LCD
LCD
LCD
LCD
LCD
LCD
Frame
Frame
23-5. SEG0 - COM0 is the voltage across a segment that is on and SEG0-
Frame
Frame
SEG0
COM0
SEG0 - COM0
SEG0
COM0
SEG0 - COM0
-
-
-1
2
1
2
1
2
1
1
2
1
1
/
/
/
/
/
/
/
/
3
3
3
3
3
3
3
3
/
/
/
-V
2
2
2
V
V
V
V
V
V
V
V
V
V
V
GND
GND
GND
-V
V
GND
V
V
GND
V
V
GND
V
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
LCD
ATmega329P/3290P
Frame
Frame
Frame
Frame
SEG0
COM1
SEG0 - COM1
SEG0
COM1
SEG0 - COM1
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