ATMEGA644P-20PQ Atmel, ATMEGA644P-20PQ Datasheet - Page 103

• Manufacturer Part Number: ATMEGA644P-20PQ
• Description: MCU AVR 64K FLASH 20MHZ 40-PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644P-20PQ

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 64KB (32K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 4K 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: 40-DIP (0.600", 15.24mm)
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8011O–AVR–07/10
Figure 12-9. Timer/Counter Timing Diagram, with Prescaler (f
Figure 12-10
mode and PWM mode, where OCR0A is TOP.
Figure 12-10. Timer/Counter Timing Diagram, Setting of OCF0x, with Prescaler (f
Figure 12-11
PWM mode where OCR0A is TOP.
Figure 12-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match mode, with Pres-
TCNTn
TCNTn
TCNTn
(clk
(clk
(clk
OCRnx
OCFnx
(CTC)
OCRnx
OCFnx
TOVn
clk
clk
clk
clk
clk
clk
I/O
I/O
I/O
I/O
I/O
I/O
Tn
Tn
Tn
/8)
/8)
/8)
shows the setting of OCF0B in all modes and OCF0A in all modes except CTC
shows the setting of OCF0A and the clearing of TCNT0 in CTC mode and fast
caler (f
clk_I/O
OCRnx - 1
MAX - 1
TOP - 1
/8)
OCRnx
MAX
TOP
ATmega164P/324P/644P
OCRnx Value
TOP
OCRnx + 1
BOTTOM
BOTTOM
clk_I/O
/8)
BOTTOM + 1
BOTTOM + 1
OCRnx + 2
clk_I/O
/8)
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