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
| Feature | Microprocessor | Microcontroller |
|---|---|---|
| Components | CPU only | CPU, memory, I/O ports, peripherals |
| Purpose | General-purpose computing | Specific control tasks in embedded systems |
| Memory | External | On-chip |
| I/O Ports | External | On-chip |
| Architecture | Von Neumann | Harvard |
| Cost | Higher | Lower |
| Power Consumption | Higher | Lower |
| Applications | Personal computers, servers, complex systems | Home appliances, automotive systems, toys |
| Processing Power | Higher | Lower |
| Development Complexity | More complex | Simpler |
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.