ATmega644 Atmel Corporation, ATmega644 Datasheet - Page 264

• Manufacturer Part Number: ATmega644
• Manufacturer: Atmel Corporation

Specifications of ATmega644

• Flash (kbytes): 64 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 32
• Ext Interrupts: 32
• Usb Speed: No
• Usb Interface: No
• Spi: 3
• Twi (i2c): 1
• Uart: 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 15
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 4
• Eeprom (bytes): 2048
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 3
• Output Compare Channels: 6
• Input Capture Channels: 1
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

23.5.2
264
ATmega644
Scanning the RESET Pin
Figure 23-4. General Port Pin Schematic Diagram
The RESET pin accepts 5V active low logic for standard reset operation, and 12V active high
logic for High Voltage Parallel programming. An observe-only cell as shown in
inserted for the 5V reset signal.
Figure 23-5. Observe-only Cell
See Boundary-scan
Description for Details!
Pxn
From System Pin
PUD:
PUExn:
OCxn:
ODxn:
IDxn:
SLEEP:
IDxn
PULLUP DISABLE
PULLUP ENABLE for pin Pxn
OUTPUT CONTROL for pin Pxn
OUTPUT DATA to pin Pxn
INPUT DATA from pin Pxn
SLEEP CONTROL
Previous
From
PUExn
Cell
ShiftDR
0
1
ClockDR
SLEEP
OCxn
ODxn
D
FF1
SYNCHRONIZER
D
L
WDx:
RDx:
WRx:
RRx:
RPx:
CLK
Q
Q
Q
Next
I/O
Cell
To
:
D
WRITE DDRx
READ DDRx
WRITE PORTx
READ PORTx REGISTER
READ PORTx PIN
I/O CLOCK
PINxn
Q
Q
To System Logic
RESET
RESET
Q
Q
Q
Q
PORTxn
DDxn
CLR
CLR
D
D
CLK
PUD
WRx
WDx
RDx
RRx
RPx
I/O
Figure 23-5
2593N–AVR–07/10
is