Hello welcome back.
So as you know embedded systems can control many different devices from small
sensors on production lines
to washing machines and control systems in space shuttles.
Each component of an embedded system is chosen for efficiency and sometimes for
future expansion.
Let's take a look at a typical embedded device based on the ARM core. An embedded
device such as a microcontroller
will typically be made of on ARM core some controllers some peripherals and some
buses.
These are the four main hardware components of an embedded device. An ARM based
microcontroller is made
of an ARM processor which controls the embedded device.
And as we shall see in this course there are different ARM processors available to suit
you the desired operating
characteristics.
The ARM processor itself is made of the core,
this is the part of the processor that processes instructions and manipulates data plus
some some surrounding
components such as memory management and caches which we shall see later.
The core is connected to the interrupt controller using a bus and also an AHB arbiter.
The AHB stands
for Advanced High Performance bus.
We shall talk about buses in the next lesson.
The AHB
arbiter is then connected to an AHB - APB bridge.
APB is another type of bus known as the ARM Peripheral Bus. From the AHB to APB
bridge peripherals
such as the real time clock (RTC),
the USART, the Ethernet and the timers are connected.
This bridge exists because based on your particular application you may want to control
your peripheral
using the advanced peripheral bus or just the simple peripheral bus.
Also memory controllers are connected to the AHB arbiter as well as an external bridge
to interface with
external bus and different kinds of memory.
So in summary this is just a simplified example of the ARM based embedded device.
This diagram is simplified
to make it easily understandable to someone new to embedded firmware development.
The yellow rectangles
are just the controllers. The controllers coordinate important functional blocks for the
system. Two commonly
used controllers are the interrupt controller and the memory controler which we shall take
a better look at. The green
rectangles are the peripherals and as you may know peripherals provide all the input
output capabilities to
the chip and sometimes responsible for the uniqueness of a particular embedded device.
The blue
lines are just buses and they are basically
used to communicate between different parts of the device.
So this is all there is to it and I'll see you in the next lesson.