Fundamentals of Microprocessors and Microcontrollers

1.1 Definitions and Basic Concepts

Microprocessor: A microprocessor is a computer processor on a single integrated circuit (IC) that contains the arithmetic, logic, and control circuitry required to perform the functions of a computer’s central processing unit (CPU). It is designed to execute a set of instructions to perform tasks such as arithmetic operations, data movement, and control operations. The microprocessor is the brain of a computer system, capable of fetching, decoding, and executing instructions from memory.

Figure 1: Microprocessor (“IBM PCMCIA Data-Fax Modem V.34 FRU 42H4326 – ZiLOG microprocessor Z80182-9359” by Raimond Spekking is licensed under CC BY-SA 4.0.)

Microcontroller: A microcontroller is a compact integrated circuit designed to govern a specific operation in an embedded system. It includes a processor, memory (RAM, ROM, EPROM), and input/output (I/O) peripherals on a single chip. Microcontrollers are used in automatically controlled devices such as automobile engine control systems, medical devices, remote controls, office machines, appliances, power tools, toys, and other embedded systems.

Figure 2: Microcontroller (Arduino microcontroller / Arduino Uno microcontroller ATmega328 / Arduino Mega 2560 / Arduino Nano ATmega328 / Arduino Pro Mini ver.3.3V ATmega328 / Photo by Arkadiusz Sikorski http://www.arq.pl/” by Arkadiusz Sikorski is licensed under CC BY 2.0.)

1.2 Historical Development

The development of microprocessors and microcontrollers has been a significant milestone in the evolution of computing technology.

Microprocessors:

• 1971: Intel introduced the first microprocessor, the Intel 4004, a 4-bit processor capable of performing basic arithmetic and logic operations.
• 1972-1978: The second generation saw the development of 8-bit microprocessors like the Intel 8008 and 8080, which were used in early personal computers.
• 1978-1980: The third generation introduced 16-bit processors such as the Intel 8086 and Motorola 68000, which offered improved performance and capabilities.
• 1981-1995: The fourth generation brought 32-bit processors like the Intel 80386, which became popular for both control applications and number-crunching operations.
• 1995-Present: The fifth generation includes 64-bit processors like the Intel Pentium series, which are used in modern computers and offer high performance and speed.

Microcontrollers:

• 1971: The first microcontroller, the TMS 1000, was developed by Texas Instruments, combining a processor, memory, and I/O on a single chip.
• 1974: Intel introduced the 8048, which became widely used in embedded systems such as PC keyboards.
• 1993: The introduction of EEPROM memory allowed for electrically erasable and programmable microcontrollers, facilitating rapid prototyping and in-system programming.
• Present: Modern microcontrollers are highly integrated and used in a wide range of applications, from consumer electronics to industrial automation.

1.3 Comparison Between Microprocessors and Microcontrollers

1.4 Basic Functions and Applications

Basic Functions of Microprocessors:

• Fetch, Decode, Execute: The microprocessor fetches instructions from memory, decodes them to understand the required operations, and executes them.
• Arithmetic and Logic Operations: Performs basic arithmetic operations (addition, subtraction) and logic operations (AND, OR, NOT).
• Data Transfer: Moves data between different parts of the system, such as from memory to registers.
• Control Operations: Manages the control signals to coordinate the activities of the system components.

Basic Functions of Microcontrollers:

• Embedded Control: Designed to perform specific control tasks within an embedded system.
• I/O Operations: Interfaces with external devices through built-in I/O ports.
• Timers and Counters: Includes peripherals for timing and counting operations.
• Analog to Digital Conversion: Converts analog signals to digital form for processing.

Applications:

• Microprocessors: Used in personal computers, servers, high-performance computing systems, and complex industrial controllers.
• Microcontrollers: Found in household appliances (washing machines, microwaves), automotive systems (engine control units), medical devices (ECG machines), and consumer electronics (remote controls, digital cameras).

Deepen your understanding: Watch the accompanying lecture video to get deeper into the concepts covered in the reading.