ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 132

• Manufacturer Part Number: ATMEGA644A-PU
• Description: IC MCU AVR 64K FLASH 40PDIP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA644A-PU

• 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): 1.8 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)
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: JTAG, TWI, SPI, USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8272A–AVR–01/10
Figure 15-11. Timer/Counter Timing Diagram, Setting of OCFnx, with Prescaler (f
Figure 15-12
frequency correct PWM mode the OCRnx Register is updated at BOTTOM. The timing diagrams
will be the same, but TOP should be replaced by BOTTOM, TOP-1 by BOTTOM+1 and so on.
The same renaming applies for modes that set the TOVn Flag at BOTTOM.
Figure 15-12. Timer/Counter Timing Diagram, no Prescaling
Figure 15-13
164A/164PA/324A/324PA/644A/644PA/1284/1284P
(PC and PFC PWM)
and ICFn
(CTC and FPWM)
OCRnx
TCNTn
OCFnx
TOVn
(Update at TOP)
(clk
clk
clk
OCRnx
I/O
TCNTn
TCNTn
as TOP)
(clk
I/O
Tn
clk
clk
/8)
I/O
(FPWM)
shows the count sequence close to TOP in various modes. When using phase and
shows the same timing data, but with the prescaler enabled.
I/O
Tn
/1)
(if used
OCRnx - 1
TOP - 1
TOP - 1
Old OCRnx Value
OCRnx
OCRnx Value
TOP
TOP
OCRnx + 1
BOTTOM
TOP - 1
New OCRnx Value
OCRnx + 2
BOTTOM + 1
TOP - 2
clk_I/O
/8)
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