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• 1. Microprocessor and Memory Basics
• What is a microprocessor and where are they used?
• Abstract system architecture
• System communication
  • Data bus, address bus, control bus
  • Reading data from memory
  • Writing data to memory
  • The Address Capacity of Memory
• Inside the microprocessor
  • The Arithmetic and Logic Unit
  • The Program Counter
  • Registers
• Inside memory
  • Memory Read and Write Operations
  • Calculating storage space
  • Address decoders
  • Tri-state buffers
  • Multiple memory chips
  • Other types of memory
  • Memory mapped input/output

Reading data from memory

The process of reading data from memory is usually referred to as "loading" data from memory into the processor. All three of the system buses are involved in this process.

• 1. Set the address (of the memory location) on the address bus.
• 2. Set the read/write wire of the control bus high (i.e. request a read operation).
• 3. Set the address valid control wire high.
• 4. The address valid signal, together with the value on the address bus will activate the chip select wire on the appropriate memory chip.
• 5. The contents of the memory location will now be placed on the data bus.
• 6. Read the value from the data bus - usually into a register in the microprocessor.
• 7. The read/write, address valid and chip select wires can now all be set low.

The read/write wire is usually labelled R / W