ATMEGA644P-20PQ Atmel, ATMEGA644P-20PQ Datasheet - Page 82

• 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

11.3.2
8011O–AVR–07/10
Alternate Functions of Port B
The Port B pins with alternate functions are shown in
Table 11-6.
The alternate pin configuration is as follows:
• SCK/PCINT15 – Port B, Bit 7
SCK: Master Clock output, Slave Clock input pin for SPI channel. When the SPI is enabled as a
slave, this pin is configured as an input regardless of the setting of DDB7. When the SPI0 is
enabled as a master, the data direction of this pin is controlled by DDB7. When the pin is forced
to be an input, the pull-up can still be controlled by the PORTB7 bit.
PCINT15, Pin Change Interrupt source 15: The PB7 pin can serve as an external interrupt
source.
• MISO/PCINT14 – Port B, Bit 6
MISO: Master Data input, Slave Data output pin for SPI channel. When the SPI is enabled as a
master, this pin is configured as an input regardless of the setting of DDB6. When the SPI is
enabled as a slave, the data direction of this pin is controlled by DDB6. When the pin is forced to
be an input, the pull-up can still be controlled by the PORTB6 bit.
PCINT14, Pin Change Interrupt source 14: The PB6 pin can serve as an external interrupt
source.
Port Pin
PB7
PB6
PB5
PB4
PB3
PB2
PB1
PB0
Alternate Functions
SCK (SPI Bus Master clock input)
PCINT15 (Pin Change Interrupt 15)
MISO (SPI Bus Master Input/Slave Output)
PCINT14 (Pin Change Interrupt 14)
MOSI (SPI Bus Master Output/Slave Input)
PCINT13 (Pin Change Interrupt 13)
SS (SPI Slave Select input)
OC0B (Timer/Conter 0 Output Compare Match B Output)
PCINT12 (Pin Change Interrupt 12)
AIN1 (Analog Comparator Negative Input)
OC0A (Timer/Conter 0 Output Compare Match A Output)
PCINT11 (Pin Change Interrupt 11)
AIN0 (Analog Comparator Positive Input)
INT2 (External Interrupt 2 Input)
PCINT10 (Pin Change Interrupt 10)
T1 (Timer/Counter 1 External Counter Input)
CLKO (Divided System Clock Output)
PCINT9 (Pin Change Interrupt 9)
T0 (Timer/Counter 0 External Counter Input)
XCK0 (USART0 External Clock Input/Output)
PCINT8 (Pin Change Interrupt 8)
Port B Pins Alternate Functions
ATmega164P/324P/644P
Table
11-6.
82