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Embedded Systems and Von Neumann (Von Neumann Model (Pros (No need to…
Embedded Systems and Von Neumann
Actuators
It is a type of motor which needs a source of energy to work normally in the form of electricity or pressure
Are used to move or control an output
Sensors
Is a converter that measures a physical quantity and converts it to a signal which is input to a system
Pros and cons of embedded systems
Pros
Easy to manage
Low cost
More specific to one task
Spend less resources
Small size and faster to load
Cons
Hardware is limited
Troubleshooting is difficult
Difficult to transfer data from one system to another
Nearly not scalable
If any problem occurs then you need to reset settings
Difficult to upgrade
Difference between embedded and non-embedded systems
Non-embedded systems are not bound by hardware and what inputs, processes and outputs they are made for or are capable of
An embedded system is a system that is normally purpose built with software embedded in the hardware to perform its specific tasks
What did Von Neumann do?
This meant that the program itself was treated with data and could henceforth be easily change by simply changing the values stored in the memory
This made computers which could carry out any instructions asked of it without having to rewire the circuits
It is stored as a series of electronical values in the CPU's memory
He devised a way that made a computer treat data and instructions in the same way
Von Neumann Model
Control Unit
- Manages the fetch, decode, execute cycle. Controls all other components
Arithmetic/Logic Unit
- Carries out calculations and logic operations. Gateway to CPU
Accumulator
- A register, which holds the intermediate results of arithmetic and logical operations without the need to write them back to main memory
Memory Unit
- Also known as the IAS (Intermediate Access Store) holds the data the CPU needs and controls access to the RAM
Output Device
- Communicates information from the CPU via the bus and registers
Input Device
- Transfers information into the CPU via the bus and registers
Pros
No need to rewire computer ciruits
Simplifies hardware
Easier to program computers
Cons
Bottleneck of information
One piece of data can be processed at a time
Fetch, Decode, Execute Cycle
If the required data is in the cache it is known as a cache hit and if the data is not available in the cache then it is known as a cache miss
If the data is not in the cache, the cache will fetch the required data/instruction from the RAM
The CPU will then request the data and instruction from the cache as and when they are needed
The CPU will then execute the instruction or process any data
The instructions and data are then transferred into the cache
The instructions and data are then transferred into the RAM which has a shorter latency time than accessing information directly from the hard drive
When a user requests a program to be loaded, the instructions and any associated data must be recalled from the non-volatile, secondary storage device