Arduino UNO Reference Design
TM
Reference Designs ARE PROVIDED "AS IS" AND "WITH ALL FAULTS". Arduino DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
REGARDING PRODUCTS, INCLUDING BUT NOT LIMITED TO, ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
USBVCC
1
GND
1
XT1R
4
3
1
EXP
GND
PAD
13
12
11 TXLED
10 RXLED
9 M8RXD
8 M8TXD
7
6
16MHz
2
1
Q2
2
5
RN1D 10K
4
1
UBOOT
2
USB boot En
1K
5 RN2D
4
C6
100n
+5V
XTAL2
2
4
6
ICSP
GND
ZIC1
1
10
9
21
20
22
7
8
RESET
XTAL2
XTAL1
AREF
AVCC
AGND
VCC
GND
(SCK)PB5
(MISO)PB4
(MOSI)PB3
(SS)PB2
(OC1)PB1
(ICP)PB0
(ADC5)PC5
(ADC4)PC4
(ADC3)PC3
(ADC2)PC2
(ADC1)PC1
(ADC0)PC0)
(AIN1)PD7
(AIN0)PD6
(T1)PD5
(T0)PD4
(INT1)PD3
(INT0)PD2
(TXD)PD1
(RXD)PD0
GND
TX
YELLOW
1K
6 RN2C
3
XTAL1
1
16MHz
XTAL2
R2
1M
XTAL1
AREF
+5V
RX
YELLOW
16MHz
+5V
100n
C5
DTR
Y2
ATMEGA8U2-MU
XT1
XT2
2
RESET
GND
ATMEGA8
M8RXD
M8TXD
GND
2
GROUND
(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
C9
22p
C8
1u
GND
GND
UCAP
UVCC
DD+
UGND
22
23
25
26
5
C10
22p
100n
C7
VCC
GND
27
31
30
29
28
VUCAP
USBVCC
RDRD+
UGND
(INT4/ICP1/CLK0)PC7
(OC1A/PCINT8)PC6
(PCINT9/OC1B)PC5
(PCINT10)PC4
(AIN2/PCINT11)PC2
AVCC
21
20
19
18
17 MISO2
16 MOSI2
15 SCK2
14
C12
22p
+5V
32
(PCINT7/OC0A/OC1C)PB7
(PCINT6)PB6
(PCINT5)PB5
RESET(PC1/DW)
(T1/PCINT4)PB4
(PD0/MISO/PCINT3)PB3
(PDI/MOSI/PCINT2)PB2
XTAL2(PC0)
(SCLK/PCINT1)PB1
(SS/PCINT0)PB0
XTAL1
RESET-EN
1
3
5
8
1
2
5
10K
6 RN1C
3
XT1
16MHz
RD+
USHIELD
BLM21
2
Y1
R3
27R
22R
5 RN3D
4
R1
RD- 1M
GND
22R
8 RN3A
1
Q1
Z1
PGB1010604
Z2
DD+
XT2
PGB1010604
XUSB
UGND
1
2
3
4
L1
P$2
P$1
P$2
P$1
USB
X2
RESET2
USBVCC
500mA
C11
22p
F1
1
U3
+5V
GND
ICSP
3
4
RESET
TS42
ICSP1
24
GND
GND
+5V
4
GND
GND
PC2 C2
47u 100n
1K
7 RN4B
2
1K
8 RN4A
1
19
18
17
16
15
14
SS
IO9
IO8
28
27
26
25
24
23
AD5
AD4
AD3
AD2
AD1
AD0
13
12
11
6
5
4
3
2
IO7
IO6
IO5
IO4
IO3
IO2
IO1
IO0
GREEN
ON
5
RN4D 1K
3
GND
6
RN4C 1K
2
+5V
ICSP
GND
GND
1K
VIN
1
2
3
4
5
6
1K
RN2B
+3V3
GND
2
4
6
GND
+5V
2
POWER
RESET
GND
1
3
5
ADJ
+5V
C3
1u
4
7
GND NC/FB
VO
VI
5 +3V3
YELLOW
L
OUT
EN
1
2
IN
RN2A
T1
FDN304V
3
3
1
PWRIN
+5V
+
D1
M7
PC1
47u
+5V
1
MC33269ST-5.0T3
IC2 GND
MC33269D-5.0
VIN
2
1
GATE_CMD
+5V
3
3
GND
GND
4
2
GND
GND
LM358D
+
4
C1
100n
IN OUT
7
6
LM358D
IC1
U1B
5
1
2
10K
8 RN1A
1
8
U1A
3
2
CMP
+3V3
3
1
7
2
+5V
RN1B 10K
Arduino may make changes to specifications and product descriptions at any time, without notice. The Customer must not
rely on the absence or characteristics of any features or instructions marked "reserved" or "undefined." Arduino reserves
these for future definition and shall have no responsibility whatsoever for conflicts or incompatibilities arising from future changes to them.
The product information on the Web Site or Materials is subject to change without notice. Do not finalize a design with this information.
VIN
C4
100n
AREF
GND
SCK
MISO
MOSI
SS
8
7
6
5
4
3
2
1
13
12
11
10
9
8
IOH
6
5
4
3
2
1
2
3
IOL
6
RN3C 22R
AD
8
7
6
5
4
3
2
1
7
RN3B 22R
7
6
5
4
3
2
1
0