Integrated Circuit Boards and Microcontrollers

Introduction

• Integrated circuit boards are crucial in household appliances and electronic devices.
• They enable multiple functions in electronic products.

Microcontroller Overview

• Microcontroller: An integrated circuit chip using VLSI technology.
• Components:
  • Central Processing Unit (CPU)
  • Memory
  • I/O (Input/Output) interfaces
• First microprocessor: Intel 4004 (1971).
• Referred to as a single-chip microcomputer, a simplified version of a computer.

Main Components of a Microcontroller

1. Central Processing Unit (CPU)

• Functions:
  • Calculation: Performs mathematical calculations.
  • Control: Manages input and output based on program code.

2. Memory

• Types:
  • Read-Only Memory (ROM): Stores user-compiled programs; CPU reads instructions from here.
  • Random Access Memory (RAM): Stores temporary data like variables generated during execution.

3. I/O Interfaces

• Facilitate communication between external circuits and the CPU.
• Functions:
  • Data Interface: Read and write external memory.
  • Control Interface: Outputs control commands (e.g., motor control, relay control).
  • Human-Computer Interaction: Interfaces like screen displays and keyboard inputs.

Workflow of a Microcontroller

1. Upload program to microcontroller's ROM via a programmer.
2. CPU executes instructions sequentially.
3. Outputs (e.g., lighting an LED) occur via the I/O interface.
4. Arithmetic instructions executed by the CPU, variables stored in RAM.

Clock and Synchronization

• Clock Signal: A high/low interval signal orchestrating synchronized module operations.
• Source: Internal RC oscillator or external crystal oscillator.
• Crystal Oscillator: Preferred due to lower error rates; sets the main frequency of the microcontroller.
• Impact: Higher frequency = higher performance.

Summary

• Microcontroller integrates CPU, memory, and I/O interfaces using VLSI technology.
• CPU handles computing and control tasks.
• ROM stores program instructions; RAM stores execution data.
• I/O interfaces manage data, control signals, and human interaction.
• Clock-driven synchronization affects overall performance.