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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

Calculating storage space

Memory chip showing attendant wires

This memory chip has 20 address wires (sometimes called address lines) and 8 data wires. It can therefore store 8 x 2²⁰ = 8388608 bits of information.

1 kilobinary byte = 2¹⁰ = 1024 bytes = 8192 bytes
1 megabinary byte = 2²⁰ = 1024 kilobytes = 1024 x 1024 bytes.

Kilobyte and megabyte are short for kilobinary byte and megabinary byte.

This memory chip can store 1 Megabyte of data.

Each bit inside the memory chip has its own memory element, which can be set low (0) or high (1). These are arranged as a matrix of rows and columns. There is one row of memory elements for each address and one column for each data wire.

The signals from the address bus are passed to a decoder, which determines which row of memory elements corresponds to the address on the bus. The decoder selects one row out of 2ⁿ possibilities where n is the number of address lines feeding into it from the bus.

Memory elements array