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Embedded Systems. By Andrew Gliga Cs 147. What are Embedded Systems?. Similar to real computers They have CPU, memory, I/O Though they have limited tasks Can only do specific things that they are designed for - PowerPoint PPT Presentation
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What are Embedded Systems?Similar to real computers
They have CPU, memory, I/O
Though they have limited tasks Can only do specific things that they are
designed for
No specific definition for Embedded Systems, some systems have one task, others have hundreds. Some have GUI, some do not even have a mode of interaction
What uses Embedded Systems?
Cars, Airplanes, Coffee Machines, MP3 players, cellphones
Basically any machine that needs to perform certain tasks
The Embedded Systems in these machines controls certain aspects, such as fuel injection, pilot controls, speedometers, and dispensing Coffee
History of Embedded Machines
Computers in the 1940's were too large and expensive to be used in portable tasks, even though they could perform simple tasks.
Over time though, with smaller and smaller computers, they could be created for specific tasks
More History Charles Stark Draper
developed the first modern Embedded Machine for the Apollo Spacecraft, called the Apollo Guadance computer that helped make the Moon landing possible.
Even More History
With the introduction of the Microprocessor, Embedded Machines were able to take smaller and smaller forms.
This allows smaller and lighter machines that control many of our devices today, such as our Cell phones, or MP3 players
Characteristics
They can only be used for specific tasks, not general tasks
They run with limited resources They can also be a part of a larger system
and used as a subsystem For example: a car is the larger system,
while the Embedded System is a subsystem of the car
Microcontrollers
Microcontrollers is what controls the embedded system
Unlike Microprocessors, they include memory and I/O. In a sense, they are like a mini computer
They implement AND, OR, XOR, NOT gates
Extremely compact and cheap
Aspects of Microcontrollers
Watchdog timers They generally keep an eye on the
system. When an error occurs in the system they
enable a failsafe mechanism. Similar as a human resets a non-
responsive machine, the Watchdog timer automatically 'resets' the Microcontroller to a normal state when it doesn't respond normally for a specified time
Systems on a Chip (SOC) Microcontrollers, while they are mini
computers still require supporting circuits. Examples: Decoders, signal converts, or
signal processors SOC incorporates all these suporting
circuits and a Microcontroller in one easy and compact chip.
They are fast, small, and compact. They even consume less memory than having all the other chips that they replace
Embedded Software
Software written for an embedded machine needs to have the specs of the machine in mind.
The software is built in the Embedded System itself
Software also can not be fine tuned after the program is embedded onto the circuit
Need to get it right the first time!
Embedded Systems Memory
The Embedded System does not use virtual memory, since it relies on being quick.
Embedded programmers have to be aware of the size of memory, since it is limited based on the machine