Arduino Uno


Arduino Uno (R3) Front View


Processor: ATmega328 (8-bit, 16MHz, 2KB RAM, 32KB Flash)
Features: 14 digital I/O pins, 6 analog input pins

POWER header:
NameFunction
-Not connected
IOREFLogic Reference (5V) (*)
RESETPCINT14/RESET pin
3.3V3.3V
5V5V
GNDGround
GND
VinInput voltage (External power)

ANALOG header:
NameMCU pinFunction
14 (A0)PC0 (23)ADC0/PCINT8
15 (A1)PC1 (24)ADC1/PCINT9
16 (A2)PC2 (25)ADC2/PCINT10
17 (A3)PC3 (26)ADC3/PCINT11
18 (A4)PC4 (27)ADC4/SDA/PCINT12
19 (A5)PC5 (28)ADC5/SCL/PCINT13

DIGITAL header:
NameMCU pinFunction
0PD0 (2)PCINT16/RXD
1PD1 (3)PCINT17/TXD
2PD2 (4)PCINT18/INT0
3PD3 (5)PCINT19/OC2B/INT1 (PWM)
4PD4 (6)PCINT20/XCK/T0
5PD5 (11)PCINT21/OC0B/T1 (PWM)
6PD6 (12)PCINT22/OC0A/AIN0 (PWM)
7PD7 (13)PCINT23/AIN1
8PB0 (14)PCINT0/CLKO/ICP1
9PB1 (15)OC1A/PCINT1 (PWM)
10PB2 (16)SS/OC1B/PCINT2 (PWM)
11PB3 (17)MOSI/OC2A/PCINT3 (PWM)
12PB4 (18)MISO/PCINT4
13PB5 (19)SCK/PCINT5 (LED)
GNDGround
AREFAREF (21)Analog Ref.
18 (A4)PC4 (27)ADC4/SDA/PCINT12 (*)
19 (A5)PC5 (28)ADC5/SCL/PCINT13 (*)

ICSP header:
NameMCU pinFunction
1PB4 (18)MISO/PCINT4
2 VCC (5 V)
3PB5 (19)SCK/PCINT5
4PB3 (17)MOSI/OC2A/PCINT3
5PC6 (1)RESET/PCINT14
6Ground

ICSP header (USB interface):
NameFunction
1MISO2
2 VCC (5 V)
3SCK2
4MOSI2
5RESET
6Ground

Notes:
(*) pins available only on Rev.3
OCxA/OCxB can be used for PWM output.
Absolute max current per pin is 40 mA (20 mA recommended).
Absolute max current for the entire package is 200 mA.