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Mind Map by eleanor croker, updated more than 1 year ago
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Created by eleanor croker
almost 7 years ago
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1.1 Systems architecture
- Embedded Systems
- An embedded system is a system that
has software embedded into hardware,
usually for a specific purpose
- Examples
- Washing
Machine
- Mobile Phones
- ATMs
- Thermostats
- Vending Machines
- Modern
Dashboards in Cars
- Supermarket
checkouts
- Washing
Machine
- An embedded system is a system that
has software embedded into hardware,
usually for a specific purpose
- What is a CPU?
- The CPU is the brain
of the computer
- The CPU is where the processing takes place, and modern
processors based on von Neumann architecture or structure.
- Also known as a microprocessor
- The CPU is the brain
of the computer
- Von Neumann architecture:
- Program Counter
- This continuously provides the CPU with the memory address
of the next instruction in the cycle to be carried out.
- This continuously provides the CPU with the memory address
of the next instruction in the cycle to be carried out.
- MDR
- Memory Data Register
- An instruction or piece of data that is fetched from
memory is temporarily stored here until it is used.
- Memory Data Register
- MAR
- Memory Address Register
- This is the location address in the memory of the next piece of
data or instruction that the CPU needs to fetch or execute.
- Memory Address Register
- Accumulator
- This is where the results of calculations
carried out by the ALU are temporarily
stored until they are needed.
- This is where the results of calculations
carried out by the ALU are temporarily
stored until they are needed.
- These are used to store
numbers .
- Program Counter
- CPU components
- ALU
- Arithmetic Logic Unit
- The ALU is divided into two units, an
arithmetic unit (AU) and a logic unit (LU).
- This is where calculations are carried out,
including mathematical tasks, logic tests,
and data comparisons.
- Arithmetic Logic Unit
- CU
- Control Unit
- This tells different parts
of the CPU what to do.
- Control Unit
- Cache
- This stores frequently
requested instructions.
- There are 3 levels
- Level One (2KB – 64KB) Instructions are first searched
in this cache. L1 cache very small in comparison to
others, thus making it faster than the rest.
- Level Three (1MB -8MB) With each
cache miss, it proceeds to the next
level cache. 3 is the largest among
the all the cache, so it's slower, but
it's still faster than the RAM.
- Level Two (256KB - 512KB) If the instructions
are not present in the L1 cache then it looks in
the L2 cache, which is a slightly larger pool of
cache, thus accompanied by some latency.
- Level One (2KB – 64KB) Instructions are first searched
in this cache. L1 cache very small in comparison to
others, thus making it faster than the rest.
- This stores frequently
requested instructions.
- ALU
- Fetch Execute Cycle
- This cycle does exactly as it says. It fetches the
instructions, decodes them, then executes them.
- The CPU can differentiate between data and
instructions. Each opcode will consist of an
instruction of N bites, which then expects the
subsequent M bytes to be data. So the CPU
uses each opcode to determine how many of
the following bytes are data, and how many
are instructions.
- This cycle does exactly as it says. It fetches the
instructions, decodes them, then executes them.
- Performance of a CPU
- Performance of a CPU is the amount of work
accomplished by a computer system.
- Clock Speed
- CPUs have a clock, which keeps all operations
in sync. The clock speed refers to the number
of times per second the clock “ticks”. Clock
speed is measured in Hertz “Hz”.
- CPUs have a clock, which keeps all operations
in sync. The clock speed refers to the number
of times per second the clock “ticks”. Clock
speed is measured in Hertz “Hz”.
- Cache Size
- Cache size refers to how big the
cache memory is. The more there
is, the more frequently-accessed
instructions can be stored.
- Cache size refers to how big the
cache memory is. The more there
is, the more frequently-accessed
instructions can be stored.
- Number of Cores
- Number of cores refers to the
number of processors inside a
CPU chip. There are two main
types of cores: Physical + Logical
- Number of cores refers to the
number of processors inside a
CPU chip. There are two main
types of cores: Physical + Logical
- More expensive, high tech computers
often have a higher clock speed, larger
cache sizes and a higher number of cores
- Performance of a CPU is the amount of work
accomplished by a computer system.
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