1.1 Sys Architecture

1.1 Sys Architecture

1. purpose of the CPU

   • This processes all the data and isntructions that make the computer work

2. components

   • ALU ( Arithmetical Logic Unit
     • Performs operations (AND, OR, NOT) and arithmetical operations.
   • control unit(CU)
     • Controls activities on the CPU( such as the flow of data between the CPU and other parts. Makes the FDE cycle happen in order
   • Cache
     • sits between the CPU and the ram. Its very fast. It keeps frequently used data so it does have to go back and forth into the RAM

3. registers

   • acumulator
     • Stores the results of the calculations done by the ALU
   • Program counter
     • Holds the memory address of the instruction for each cycle
   • MDR (memory data register)
     • holds data that has been fetched from the memory
   • MAR (memory address register
     • holds memory address about to be used in the PC

4. FDE cycle

   • 1. The memory address from the program counter is copied in the MAR
   • 2. An instruction is fetched from the address stored in the MAR
   • 3. The fetched instruction is moved to the MDR
   • 4. The value in the program counter is changed to point the new direction

5. Embedded system

   • A computer system built into another machine

6. Characteristics

   • clock speed
     • Number of instructions that can be carried out in a second (Hz) – These days in Ghz (Billion)
   • Cache size
     • – A larger cache gives the CPU faster access to commonly used data. It is faster than RAM.
   • number of cores
     • – Each core processes data independently of the rest. The more cores, the faster it can process. These days we have dual or quad cores but can have up to 6 or 8.