Microprocessors and Microcontrollers

• Microcomputer: A computer using a microprocessor as its CPU, incorporating memory and I/O.
• Microprocessor: A silicon chip containing the ALU, register circuits, and control circuits.
• Microcontroller: A single silicon chip integrating a microprocessor, memory, and I/O.
• A microprocessor processes binary numbers (0s and 1s) by performing operations based on its design.

Microprocessor History

• Early processors in the late 1960s were built using discrete elements, which were large and slow.
• The invention of the microchip in the early 1970s placed all processor components on a single silicon piece, significantly reducing size and increasing speed.

Microprocessor Definition

• Microprocessors are programmable devices that take in numbers, perform arithmetic or logical operations according to a program stored in memory, and produce results.
• Programmable: Microprocessors can execute different sets of operations based on the sequence of instructions in a program.
• Instruction Set: Each microprocessor is designed with a specific set of operations, which defines its capabilities.
• Input Devices: Microprocessors receive data from input devices like keyboards, mice, and switches.
• Microprocessors operate using binary numbers.
• Bit: A single binary digit.
• Word: A group of bits that the microprocessor processes together; the word size indicates processing ability.

Words, Bytes, and Sizes

• Early microprocessors (e.g., Intel 8088, Motorola 6800) used 8-bit words.
• 8-bit processors process information in 8-bit chunks.
• Later microprocessors (e.g., 8086, 68000) used 16-bit words.
• Byte: A group of 8 bits (half-word).
• Nibble: A group of 4 bits.
• Long Word: A group of 32 bits.
• Current processors manipulate at least 32 bits, with some processing 64, 80, or 128 bits.

Arithmetic and Logic Operations

• Microprocessors include arithmetic operations like addition and subtraction in their instruction sets.
• Many also include multiplication, division, and complex operations like square root.
• Logic operations: AND, OR, XOR, shift left, shift right, etc. The range of operations defines the microprocessor's instruction set.

Memory

• Memory: Storage locations for information not currently in use.
• Memory consists of storage devices, typically grouped into bytes (8 bits).
• Memory is measured by the number of bytes it can hold (KB, MB, GB).
  • Kilobyte (KB): 2^10 = 1024 bytes.
  • Megabyte (MB): 1024 KB.
  • Gigabyte (GB): 1024 MB.
• Programs are stored in memory.
• Microprocessors fetch instructions from memory to execute them.
• Data is read from memory when needed and results are written back to memory.

Output

• Results of program execution must be presented in a human-readable form through output devices.
• Output devices: Monitors, printers, LEDs, etc.

Microprocessor-Based System

• A microprocessor-based system consists of memory, input, and output components.

Internal Microprocessor Units

• Arithmetic/Logic Unit (ALU)
• Control Unit
• Register array for data manipulation

Memory Subsystem

• Registers inside the microprocessor
• Read Only Memory (ROM): Stores unchanging information.
• Random Access Memory (RAM): Stores user-supplied information like programs and data.

Memory Map

• Memory Map: A visual representation of the address range, showing the locations of memory chips.