3.2. ATmega328P
Speed [MHz]
(3)
Power Supply [V] Ordering Code
(2)
Package
(1)
Operational Range
20 1.8 - 5.5
ATmega328P-AU
ATmega328P-AUR
(5)
ATmega328P-MMH
(4)
ATmega328P-MMHR
(4)(5)
ATmega328P-MU
ATmega328P-MUR
(5)
ATmega328P-PU
32A
32A
28M1
28M1
32M1-A
32M1-A
28P3
Industrial
(-40°C to 85°C)
ATmega328P-AN
ATmega328P-ANR
(5)
ATmega328P-MN
ATmega328P-MNR
(5)
ATmega328P-PN
32A
32A
32M1-A
32M1-A
28P3
Industrial
(-40°C to 105°C)
Note: 
1. This device can also be supplied in wafer form. Please contact your local Atmel sales office for
detailed ordering information and minimum quantities.
2. Pb-free packaging, complies to the European Directive for Restriction of Hazardous Substances
(RoHS directive). Also Halide free and fully Green.
3. Please refer to Speed Grades for Speed vs. V
CC
4. Tape & Reel.
5. NiPdAu Lead Finish.
Package Type
28M1 28-pad, 4 x 4 x 1.0 body, Lead Pitch 0.45mm Quad Flat No-Lead/Micro Lead Frame Package (QFN/
MLF)
28P3 28-lead, 0.300” Wide, Plastic Dual Inline Package (PDIP)
32M1-A 32-pad, 5 x 5 x 1.0 body, Lead Pitch 0.50mm Quad Flat No-Lead/Micro Lead Frame Package (QFN/
MLF)
32A 32-lead, Thin (1.0mm) Plastic Quad Flat Package (TQFP)
Atmel ATmega328/P [DATASHEET]
Atmel-42735B-328/P_Datasheet_Summary-11/2016
7
4. Block Diagram
Figure 4-1. Block Diagram
CPU
USART 0
ADC
ADC[7:0]
AREF
RxD0
TxD0
XCK0
I/O
PORTS
D
A
T
A
B
U
S
GPIOR[2:0]
SRAM
OCD
EXTINT
FLASH
NVM
programming
debugWire
I
N
/
O
U
T
D
A
T
A
B
U
S
TC 0
(8-bit)
SPI 0
AC
AIN0
AIN1
ADCMUX
EEPROM
EEPROMIF
TC 1
(16-bit)
OC1A/B
T1
ICP1
TC 2
(8-bit async)
TWI 0
SDA0
SCL0
Internal
Reference
Watchdog
Timer
Power
management
and clock
control
VCC
GND
Clock generation
8MHz
Calib RC
128kHz int
osc
32.768kHz
XOSC
External
clock
Power
Supervision
POR/BOD &
RESET
XTAL2 /
TOSC2
RESET
XTAL1 /
TOSC1
16MHz LP
XOSC
PCINT[23:0]
INT[1:0]
T0
OC0A
OC0B
MISO0
MOSI0
SCK0
SS0
OC2A
OC2B
PB[7:0]
PC[6:0]
PD[7:0]
ADC6,ADC7,PC[5:0]
AREF
PD[7:0], PC[6:0], PB[7:0]
PD3, PD2
PB1, PB2
PD5
PB0
PB3
PD3
PD4
PD6
PD5
PB4
PB3
PB5
PB2
PD6
PD7
ADC6, ADC7
PC[5:0]
PD0
PD1
PD4
PC4
PC5
Atmel ATmega328/P [DATASHEET]
Atmel-42735B-328/P_Datasheet_Summary-11/2016
8
5. Pin Configurations
5.1. Pin-out
Figure 5-1. 28-pin PDIP
Power
Ground
Programming/debug
Digital
Analog
Crystal/Osc
(PCINT14/RESET) PC6
(PCINT16/RXD) PD0
(PCINT17/TXD) PD1
(PCINT18/INT0) PD2
(PCINT19/OC2B/INT1) PD3
(PCINT20/XCK/T0) PD4
VCC
GND
(PCINT6/XTAL1/TOSC1) PB6
(PCINT7/XTAL2/TOSC2) PB7
(PCINT21/OC0B/T1) PD5
(PCINT22/OC0A/AIN0) PD6
(PCINT23/AIN1) PD7
(PCINT0/CLKO/ICP1) PB0
PC5 (ADC5/SCL/PCINT13)
PC4 (ADC4/SDA/PCINT12)
PC3 (ADC3/PCINT11)
PC2 (ADC2/PCINT10)
PC1 (ADC1/PCINT9)
PC0 (ADC0/PCINT8)
GND
AREF
AVCC
PB5 (SCK/PCINT5)
PB4 (MISO/PCINT4)
PB3 (MOSI/OC2A/PCINT3)
PB2 (SS/OC1B/PCINT2)
PB1 (OC1A/PCINT1)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Atmel ATmega328/P [DATASHEET]
Atmel-42735B-328/P_Datasheet_Summary-11/2016
9

ATMEGA328P-AU

Mfr. #:
Manufacturer:
Microchip Technology / Atmel
Description:
8-bit Microcontrollers - MCU 32KB In-system Flash 20MHz 1.8V-5.5V
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union