Controllers and Operations - 1

Introduction to Microprocessors and Microcontrollers

• Q: Where are these examples present in day-to-day usage?

Applications of Microcontrollers

Common Applications

• Consumer Electronics: TVs, washing machines, microwave ovens
• Automotive: Engine control units, airbags, ABS
• Industrial Automation: Process controllers, robotics
• IoT Devices: Smart home systems, wearables
• Medical Devices: ECG machines, glucose monitors

Features of 8051 Microcontroller

• 8-bit microcontroller
• 4 KB ROM (programmable memory)
• 128 bytes RAM
• 32 I/O pins (organized into 4 ports)
• Two 16-bit timers/counters
• Full-duplex UART for serial communication Q: What is Full-duplex?
• Interrupt system with 5 sources

Architecture of 8051

Key Components

1. ALU (Arithmetic Logic Unit): Performs arithmetic and logical operations.
2. Registers: Accumulator (A), B register, general-purpose registers.
3. Memory:
   • Program memory (ROM)
   • Data memory (RAM)
4. I/O Ports: 4 bidirectional 8-bit ports.
5. Timers/Counters: Two 16-bit timers.
6. Serial Communication: UART.
7. Interrupts: 5 interrupt sources, including external and timer interrupts.

Pin Diagram of 8051

1. Port P0 (Pins 32-39): Multiplexed as data and address bus.
2. Port P1 (Pins 1-8): General-purpose I/O.
3. Port P2 (Pins 21-28): High-order address bus in external memory interfacing.
4. Port P3 (Pins 10-17): Dual-purpose (I/O + special functions like serial input/output).
5. Other Pins:
   • Vcc (Pin 40): +5V supply
   • GND (Pin 20): Ground
   • RST (Pin 9): Reset input
   • EA (Pin 31): External Access enable
   • ALE (Pin 30): Address Latch Enable
   • PSEN (Pin 29): Program Store Enable

Memory Organization of 8051

Internal Memory

1. RAM:
   • 128 bytes divided into:
     • 32 bytes: General-purpose registers (R0 to R7 for 4 banks).
     • 16 bytes: Bit-addressable memory.
     • 80 bytes: General-purpose memory.
   • SFRs: Control I/O, timers, and serial communication.
2. ROM:
   • 4 KB for program storage.
   • Address range: 0000H - 0FFFH.

External Memory

• Supports up to 64 KB of program memory and 64 KB of data memory.
• Uses Port 0 and Port 2 for data and address buses.

Interrupt Structure of 8051

Features of 8051 Interrupt System

• 5 interrupt sources:
  1. External Interrupt 0 (INT0)
  2. Timer 0 Overflow
  3. External Interrupt 1 (INT1)
  4. Timer 1 Overflow
  5. Serial Communication Interrupt
• Interrupt Priority Levels:
  • Low priority
  • High priority (overrides low-priority interrupts)
• IE (Interrupt Enable) Register:
  • Enables or disables specific interrupts.
• IP (Interrupt Priority) Register:
  • Sets priority levels for interrupts.

Interrupt Execution

• When an interrupt occurs, the microcontroller:
  1. Suspends the current task.
  2. Jumps to the corresponding Interrupt Service Routine (ISR).
  3. Resumes the main program after ISR execution.

Summary

• Microprocessor vs Microcontroller: Microcontrollers are specialized for embedded systems.
• 8051 Features: 8-bit architecture, 4 KB ROM, 128 bytes RAM, and 32 I/O pins.
• Applications: Widely used in IoT, automation, and consumer electronics.
• 8051 Architecture: Integrated ALU, memory, timers, and serial ports.
• Pin Diagram and Memory: Essential for hardware interfacing and program execution.

Questions and Discussion

• 2 doubts from each (minimum)
• In 1 line, tell what did you understood from this presentation.

References:

https://www.tutorialspoint.com/microprocessor/microcontrollers_8051_architecture.htm

https://www.geeksforgeeks.org/whats-difference-between-microcontoller-%C2%B5c-and-microprocessor-%C2%B5p/

https://www.geeksforgeeks.org/microprocessor-tutorials/