ATMEGA644P-20PQ Atmel, ATMEGA644P-20PQ Datasheet - Page 78

• 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
8011O–AVR–07/10
Alternate Port Functions
Most port pins have alternate functions in addition to being general digital I/Os.
shows how the port pin control signals from the simplified
ridden by alternate functions. The overriding signals may not be present in all port pins, but the
figure serves as a generic description applicable to all port pins in the AVR microcontroller
family.
Figure 11-5. Alternate Port Functions
Note:
PTOExn:
PUOExn:
PUOVxn:
DDOExn:
DDOVxn:
PVOExn:
PVOVxn:
DIEOExn: Pxn DIGITAL INPUT-ENABLE OVERRIDE ENABLE
DIEOVxn:
SLEEP:
Pxn
1. WRx, WPx, WDx, RRx, RPx, and RDx are common to all pins within the same port. clk
SLEEP, and PUD are common to all ports. All other signals are unique for each pin.
Pxn PULL-UP OVERRIDE ENABLE
Pxn PULL-UP OVERRIDE VALUE
Pxn DATA DIRECTION OVERRIDE ENABLE
Pxn DATA DIRECTION OVERRIDE VALUE
Pxn PORT VALUE OVERRIDE ENABLE
Pxn PORT VALUE OVERRIDE VALUE
Pxn DIGITAL INPUT-ENABLE OVERRIDE VALUE
SLEEP CONTROL
Pxn, PORT TOGGLE OVERRIDE ENABLE
1
0
1
0
1
0
1
0
PUOExn
PUOVxn
PVOExn
PVOVxn
DIEOExn
DIEOVxn
SLEEP
DDOExn
DDOVxn
(1)
SYNCHRONIZER
D
L
SET
CLR
Q
Q
ATmega164P/324P/644P
PUD:
WDx:
RDx:
RRx:
WRx:
RPx:
WPx:
clk
DIxn:
AIOxn:
D
PINxn
CLR
I/O
Q
Q
:
RESET
PORTxn
Q
Q
CLR
D
RESET
Q
Q
DDxn
CLR
Figure 11-2 on page 73
WRITE DDRx
WRITE PORTx
PULLUP DISABLE
READ DDRx
READ PORTx REGISTER
READ PORTx PIN
WRITE PINx
I/O CLOCK
DIGITAL INPUT PIN n ON PORTx
ANALOG INPUT/OUTPUT PIN n ON PORTx
D
1
0
RRx
clk
PUD
WDx
RDx
DIxn
AIOxn
RPx
I/O
WRx
PTOExn
WPx
can be over-
Figure 11-5
I/O
,
78