ATmega325P Atmel Corporation, ATmega325P Datasheet - Page 23

• Manufacturer Part Number: ATmega325P
• Manufacturer: Atmel Corporation

Specifications of ATmega325P

• Flash (kbytes): 32 Kbytes
• Pin Count: 64
• Max. Operating Frequency: 20 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 54
• Ext Interrupts: 17
• Usb Speed: No
• Usb Interface: No
• Spi: 2
• 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): 2
• Eeprom (bytes): 1024
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: Yes
• 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: 4
• Input Capture Channels: 1
• Pwm Channels: 4
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

7.6
7.6.1
7.6.2
8023F–AVR–07/09
Register Description
EEARH and EEARL – The EEPROM Address Register
EEDR – The EEPROM Data Register
reserved in Opcode for the IN and OUT instructions. For the Extended I/O space from 0x60 -
0xFF in SRAM, only the ST/STS/STD and LD/LDS/LDD instructions can be used.
For compatibility with future devices, reserved bits should be written to zero if accessed.
Reserved I/O memory addresses should never be written.
Some of the Status Flags are cleared by writing a logical one to them. Note that, unlike most
other AVRs, the CBI and SBI instructions will only operate on the specified bit, and can therefore
be used on registers containing such Status Flags. The CBI and SBI instructions work with reg-
isters 0x00 to 0x1F only.
The I/O and peripherals control registers are explained in later sections.
• Bits 15:11 – Res: Reserved Bits
These bits are reserved and will always read as zero.
• Bits 10:0 – EEAR10:0: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the 1K
bytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and 1023.
The initial value of EEAR is undefined. A proper value must be written before the EEPROM may
be accessed.
Note:
• Bits 7:0 – EEDR7:0: EEPROM Data
For the EEPROM write operation, the EEDR Register contains the data to be written to the
EEPROM in the address given by the EEAR Register. For the EEPROM read operation, the
EEDR contains the data read out from the EEPROM at the address given by EEAR.
Bit
0x22 (0x42)
0x21 (0x41)
Read/Write
Initial Value
Bit
0x20 (0x40)
Read/Write
Initial Value
EEAR10 is only valid for ATmega645P and ATmega6450P.
EEAR7
MSB
R/W
R/W
15
7
0
R
X
–
7
0
EEAR6
R/W
R/W
14
6
0
R
X
–
6
0
EEAR5
R/W
R/W
13
5
0
R
X
–
5
0
EEAR4
R/W
R/W
12
R
4
0
–
4
0
X
EEAR3
R/W
R/W
11
R
3
0
–
3
0
X
ATmega325P/3250P
EEAR10
EEAR2
R/W
R/W
R/W
10
2
0
2
X
X
EEAR9
EEAR1
R/W
R/W
R/W
9
1
X
X
1
0
EEAR8
EEAR0
R/W
R/W
LSB
R/W
8
0
X
X
0
0
EEARH
EEARL
EEDR
23