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| Microcontroller Block Diagram by Ralf Fickert |
The high level Microcontroller Block Diagram above hopefully makes it easy for the
children to understand the basic components common to any Microcontroller.
It
is suggested to have a poster of this Microcontroller Block Diagram on a wall
in the Lab always visible for the children as well as to give them a copy of it.
In case that you are executing the Lab in another Language than English I would
highly recommend to keep the diagram in English and translate it during talking
to the children into their language when you are executing the Lab. This will
help the children to learn the English terminologies as a side effect of the
Lab. By doing so the children will start to understand how important the English
language is in order to have the broadest access to information and as well to worldwide resources/communities.
Having the capability to collaborate world wide will enable them to participate,
learn, share with project teams which are not necessarily in the same country
in which the children live – that will not only help the children to bring their dreams into
the real world but also to give them early access to new technologies and
knowledge. Being able to collaborate world wide ensures also a great world wide
network for the children’s future.
Working
with the Microcontroller is fun – the Microcontroller is the Portal to the real
world.
A lot of Toys and equipment’s are using Microcontrollers such as Robosapien,
Battleships, SmartPhones, Oven, TV Remote Control, Security systems etc. SmartHomes are impossible without using Microcontrollers
– so for the children it is important to learn how Microcontroller work and to
be able to invent their own Microcontroller based SmartHomes equipments or at
least to be able to modify them to ensure the SmartHomes is not going to be an
external controlled prison at the end.
Major
manufacturers of microcontrollers are Atmel Corp. , Microchip Technology Inc. and Texas
Instruments Inc.
We will
use the Atmel
Microcontroller AVR Mega: ATMEGA168-20PU, DIP-28 for our Lab.
Central
Processing Unit (CPU)
The
Central Processing Unit (red box) short CPU is the brain of the Microcontroller.
And the same as our Brain does the CPU of the Microcontroller interpret, process,
act and create new information on the information it receives. In order to act
with the real world the CPU needs sensors to understand the environment such as
temperature, humidity, speed, light conditions, heart beats, sugar level , if a
door is open or closed etc. and the CPU needs actuators such as motors, valves,
sounds etc. to impact the real world.
Memory
Random Access Memory (RAM)
The RAM (right
light blue box) can be compared to our short term memory. The RAM is used to
keep the current important information in focus such as our brain does. The information
stored in the RAM is lost after a power cut, reset or restart of the
Microcontroller. So information stored in the RAM is volatile.
Flash Memory
The Flash
(right light blue box) is the memory where the compiled program code is stored.
The Flash is non-volatile and will not be lost after a power cut, reset or restart
of the Microcontroller.
Electrically Erasable Programmable
Read-Only Memory (EEPROM)
The
EEPROM (right light blue box) provides a non-volatile memory for storing data.
Clocks/Counters/Timers
The Clocks/Counters/Timers
(top dark blue box) are important as they provide the Microcontroller with a
sense of time. The AVR has multiple Clocks/Counters/Timers which are based on
the same common time base ensuring everything is running nicely synchronized
together. Clocks/Counters/Timers are used by RAM, Flash, EEPROM, Input and
output peripherals.
Oscillator
The
Oscillator (bottom dark blue box) sets the chips internal rate and controls how
much work can be done in a given time. The oscillators speed is like the heartbeat
of the chip.
Interrupt Request (IRQ)
The
Interrupt Request (bottom black box) sends an interrupt request to the CPU to
stop whatever it is doing at the moment to be able to react on a specific event
which just occurred.
Peripherals Input/Output
The Peripherals
Input/Output (top black box) provide the Microcontroller with the capability to
interact and communicate with the Real World via sensors or actuators.
Sensors
will provide the Microcontroller with information of the current state of the
environment such as current temperature, speed, humidity, blood pressure, GPS
position, power is on, window is open etc.
Human’s sensors would be eyes, ears, nose, tongue, skin, etc.
Actuators
enable the Microcontroller to physically act in the Real World based on the
information received by the sensors or instructions of the program.
Actuators could for example close an open window automatically when we leave
the house, or turn down the heating if the temperature reached a threshold,
execute an alarm in the case movements are recognized within a monitored room, stop
a robot when an obstacle is detected etc.
Human’s
actuators would be hand, fingers, knees, elbows, mouth etc.
Data Bus
The Data
Bus transports the information from one component to the desired other
component. For example the CPU could request data from the Memory – the data
from the memory would be put onto the data bus and received by the CPU – the CPU
then processes this information and could then base on the result of the information
analysis send the request via the data bus to an actuator like a motor to turn
until a window is closed.
The data
bus is the communication vehicle between all components connected to the bus and
via the peripherals even the real world is part of the communication.
I hope
this document is useful for you,
Ralf
