1.1 Revision.

1.1 Revision.

1. Fetch - Decode - Execute: how the CPU processes instructions:

   • Fetch: The processor checks the program counter to see which instruction to run next. The program counter gives an address value in the memory of where the next instruction is . The processor fetches instruction value from this memory location
   • Decode: Decoding the instructions in the ALU (Arithmetic Logic Unit), storing the result in this in the CIR (current instruction register).
   • Execute: The instruction is performed. Once this is complete, the processor goes back to the program counter to find the next instruction.

2. CPU

   • Fetches instruction (from memory)
     • Fetches data (from memory)
       • Decodes instructions
         • Execute instructions
   • Clock speed = The number of fetch decode execute cycles
   • Cache size = The holding area for data from the RAM - stores frequently used instructions. the more cache a CPU has the less time spent accessing memory this means it can get instructions quicker.
   • Cores = the number of processors in the CPU. the more cores a cpu has the more instructions it can carry out per second.

3. Embedded Systems are designed for a fixed purpose and are a part of a larger system

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