Deciphering the ATMega Datasheet and Arduino Schematics - Exploring Arduino: Tools and Techniques for Engineering Wizardry - page 346

VIN

+5V

X1
PWERSUPPLY_DC21MMX

CMP 13

U1
NCP1117ST50T3G

+5V
+5V

3 U5A

+

1 3 VIN3 4

2

C1
100n

3

+3V3 2 IN OUT

-

LMV358IDGKR 5

6 -

D1
M7
PC1
47u

SCK U5B

+

7

PWRIN + +

PC2C2
47u100n

LMV358IDGKR

GND GND

GND GND GND GND

+5V

GND

U2
IN

GND

1
3
2

5 + 3V3 +5V

USBVCC +5V

OUT

GREEN
ON

+5V POWER

ON/OFF C3

4 5
RN4D 1K
RN4C 1K

1

1u

4 2

GND C/FB RESET

3 6

LP2985-33DBVR +3V3 4

GND GND 5

Arduino(TM) UNO Rev3

6

7

VIN 8

+5V

GND 8 x 1F-H8.5

GND

ICSP1
1
3
5

MISO2
SCK2
RESET2

+5V

2
4
6

GND

ICSP

MOSI2 C4

100n

1
5

2
6

10X1F-H8.5

3 4

RESET-EN

3X2 M AD5/SCL

AD4/SDA

10
9

SCL
SDA

1 2 +5V

U3 AREF

GND

8

GND 3X2 M GND

21
20
19
18
17
16
15

PB7
PB6
PB5
PB4
MISO2
MOSI2
SCK2

7

(PCINT7/OC0A/OC1C)PB7

SCK
MISO
MOSI
SS

6

(PCINT6)PB6
(PCINT5)PB5
(T1/PCINT4)PB4
(PD0/MISO/PCINT3)PB3
(PDI/MOSI/PCINT2)PB2

13

RESET2 24 5

RESET(PC1/DW) 12

F1
MF-MSMF050-2 500mA

ZU4

USBVCC
22R RN2A

4

USB-B_TH

11

RESET

XT2 1 19

18
17
16
15
14

3

RESET (SCK)PB5

(MISO)PB4
(MOSI)PB3
(SS)PB2
(OC1)PB1
(ICP)PB04

10

X2 2 2

XTAL2(PC0) 9

1 XUSB GND 1

8 1 R1

1M

XTAL2

(SCLK/PCINT1)PB1 8

1
XT1

2
3
4

D- RD-

RD+

14 R2

1M

10
9

SS
IO9
IO8

XTAL1 (SS/PCINT0)PB0 XTAL2

XTAL1

D+ 22R RN3A XT1 IOH

6X1F-H8.5 5 4 XTAL1

32 22

23
25
26

CSTCE16M0V53-R0 16 MHZ
AREF

6

AVCC (INT4/ICP1/CLK0)PC7

(OC1A/PCINT8)PC6
(PCINT9/OC1B)PC5
(PCINT10)PC4

+5V

21
20
22
7
8

28
27
26
25
24
23

AD5/SCL
AD4/SDA
AD3
AD2
AD1
AD0

5

AREF
AVCC
AGND
VCC
GND

(ADC5)PC5
(ADC4)PC4
(ADC3)PC3
(ADC2)PC2
(ADC1)PC1
(ADC0)PC0

4

4

3

VCC

+5V

3 5

13
12
11
10
9
8

2

GND (AIN2/PCINT11)PC2

(CTS/HWB/AIN6/TO/INT7)PD7
(RTS/AIN5/INT6)PD6
(XCK/AIN4/PCINT12)PD5
(INT5/AIN3)PD4
(TXD1/INT3)PD3
(RXD1/AIN1/INT2)PD2
(AIN0/INT1)PD1
(OC0B/INT0)PD0

1

GND

C6
100n

TP_VUCAP
USBVCC
RD-
RD+
UGND

27
31
30
29
28

AD
8X1F-H8.5

UCAP
UVCC
D-
D+
UGND
PAD
ATMEGA16U2-MU(R)

USHIELD

TXLED
RXLED
M8RXD
M8TXD

13
12
11
6
5
4
3
2

IO7
IO6
IO5
IO4
IO3
IO2
IO1
IO0

(AIN1)PD7
(AIN1)PD7
(T1)PD5
(T0)PD4
(INT1)PD3
(INT0)PD2
(TXD)PD1
(RXD)PD0

+5V 8

7

1K RN2C 7

6

100n
C7

6 3 GND 6

5

7
6

5

TX
YELLOW

4

21 33

4

3

C8
1u

3

2

GROUND

GND RN2B 2

1

7 2 1

GND

0

ATMEGA328P-PU
M8RXD

RX
YELLOW

1K IOL

1K RN4B
7 2
1K RN4A
8

M8TXD

1

2 7
RN3B 22R

3 6
RN3B 22R

Figure A-5: Arduino Uno Rev 3 schematic

Credit: Arduino, www.arduino.cc