Hardware Reference
In-Depth Information
Galileo has 512 kilobytes of RAM built into the processor and an addi-
tional 256 megabytes of RAM on these chips. When the board is powered
down, the data stored in RAM is lost. Any data that should be saved (such
as your code) must be stored on the microSD card.
Flash memory (3)
The
flash memory
acts like the hard drive of Galileo. Unlike with RAM,
any data stored here is saved even after the board is shut down and the
power is disconnected. For this reason, it's where the board's software
and operating system are stored. It can hold 8 megabytes of data, most
of which is taken up by Galileo's operating system.
MicroSD card slot (4)
If you need more space for larger programs or to store data, you can
insert a
microSD card
into this slot. MicroSD cards are just like the mem-
ory cards that you insert into a digital camera to save photographs. You
can even load an operating system onto the card and boot off of it instead
of the on-board Flash memory. You'll need to do this if you want addi-
tional functionality like WiFi and access to the webcam because those
drivers can't fit onto the 8 megabytes of on-board Flash memory. Galileo
can use a card that's up to 32 gigabytes in size. See
Appendix D
for more
information.
Arduino expansion pins (5)
Using these pins, you'll be able to connect to the inputs and outputs on
the Galileo. You'll either use
jumper wires
to connect the pins to a
bread-
board
for prototyping, or you'll use an Arduino
shield
to add functionality
to your board. We'll cover these components a bit more in
“Helpful Tools
and Components” on page 13
.
USB client port (6)
You'll use this port to connect your Galileo to the USB port on your com-
puter. Once it's connected, you can upload your code and communicate
with it. Always connect the power supply before plugging the Galileo into
your computer over USB.
USB host port (7)
This port allows you to connect USB computer peripherals to your Gal-
ileo. It could be accessories such as webcams, sound devices, storage,
and much more.
Serial port (8)
This may look like a headphone jack, but it's not meant for audio. It's
actually a
serial port
, used for interacting with the Galileo's Linux oper-
ating system via a text-based command line environment. See
Appen-
dix H
for more information.
Power input (9)
This is where you'll plug in Galileo's power adapter. You must plug in the
AC adapter when using Galileo. You must always power the board
