ATMEGA644A-PU Atmel, ATMEGA644A-PU Datasheet - Page 104

• 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 14-9. Timer/Counter Timing Diagram, with Prescaler (f
Figure 14-10
mode and PWM mode, where OCR0A is TOP.
Figure 14-10. Timer/Counter Timing Diagram, Setting of OCF0x, with Prescaler (f
Figure 14-11
PWM mode where OCR0A is TOP.
Figure 14-11. Timer/Counter Timing Diagram, Clear Timer on Compare Match mode, with Pres-
164A/164PA/324A/324PA/644A/644PA/1284/1284P
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
OCRnx Value
TOP
OCRnx + 1
BOTTOM
BOTTOM
clk_I/O
/8)
BOTTOM + 1
BOTTOM + 1
OCRnx + 2
clk_I/O
/8)
104