Instructions

A: 7 to 12VDC input
2.1mm x 5.5mm
Male center posive
B: Voltage regulator
C: 16MHz crystal
D: ATmega16U2
Microcontrller IC/USB Controller
E: USB-B port to computer
F: Reset buon
G: ICSP for USB interface
H: (I2C) SCL-Serial clock
I: (I2C) SCL-Serial data
J: Pin-13 LED
K: (SPI) SCK-Serial clock
L: (SPI) MISO-Master-in , slave-out
M: (SPI) MOSI-Master-out , slave-in
N: (SPI) SS-Slave select
O: Interrupt 1
P: Interrupt 2
Q: TXD
R: RXD
S: RESET
T: SCK
U: MISO
V: VCC
W: MOSI
X: GND
Y: ATmega328 microcontroller IC
Z: ICSP for ATmega328