Hardware Reference
In-Depth Information
Analogue and Digital
Inside most computers you will find digital signals - that is, signals where it only matters if
they are on or off. Usually there is a difference of a few volts between a signal being on or off.
Data is sent by a code of ons and offs, typically referred to as 1s and 0s. A small change in volt-
age due to radio or magnetic interference is usually not large enough to change the meaning.
Analogue signals tend to only be used in modern computers where they have to connect
with something physical. An analogue signal typically represents data as a range of volt-
ages. As such, a small change in voltage means a different value will be read. This means
the data can be changed by electrical interference.
VGA monitors represent different colours with different voltages. Consequently, any inter-
ference will affect what is shown on the screen, and the image is degraded! Small amounts
of interference will have no effect on digital data for HDMI. However, if the interference is
strong enough, then all data will be corrupted and no image will be transmitted.
Connecting to a Network
The Raspberry Pi has an Ethernet socket that allows your Pi to connect to the Internet or
your home network. You can download new software and updates, or browse the web. You
could even run your own web server!
If you will be using a network, connect a network cable on the right side as shown in Figure
A-9. Although the Raspberry Pi uses the network to set its clock and to download updates
and new programs, it will work without a network connection.
Figure A-9:
Network
connection.
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