Hello fellas welcome back.
So in this lesson we're going to talk about the ARM bus technology and the AMBA bus
protocol.
So this our simplified ARM based embedded device from before and the buses are the
blue lines as indicated
in the diagram.
So basically there are two classes of devices connected to the bus.
There is the bus master and the bus slave. The bus master is often a logical device
capable of initiating
data transfer with another device and the slave is capable of only responding to a
transfer request
from the master.
A bus has two architecture levels
and the first level is known as the physical level,
the second level is known as the protocol level. The physical level deals with the
electrical characteristics
of the bus and things like that bus width, for example 16-bit, 32-bit 8-bit etc..
We shall look at this stuff later.
The bus protocol dictates the rules
the bus master and the bus slave uses to communicate.
Now let's give a short overview of the AMBA bus protocol.
The AMBA stands for Advanced Micro-controller Bus Architecture and it's the widely
adopted on-chip
architecture used for ARM processors. The very first AMBA buses where the ARM
system bus and
the ARM peripheral bus. Later on ARM introduced the ARM high performance bus. Using
the AMBA protocol peripheral designers can
reuse the same design on multiple projects.
The AHP provides a higher throughput than the ASB and the APB.
Because it is a sort of centralized multiplex bus scheme which we shall look out later
rather than
a bi-directional design like the ASB and the APB.
And because of this AHB busses are able to run at higher clock frequencies.
So this is all there is to it and I'll see you in the next lesson.