Summary of "Lec-4: Internal Architecture of 8085 Microprocessor | Working of 8085"

Summary of the Video: Internal Architecture of 8085 Microprocessor

The video provides an in-depth explanation of the internal architecture and working of the 8085 Microprocessor. The speaker emphasizes the importance of understanding the basic structure and functionality of the 8085 as a foundational element for modern microprocessors.

Main Ideas and Concepts:

Introduction to 8085 Microprocessor:
- The speaker shares personal experiences of learning about the 8085 during their B.Tech studies, highlighting the complexity of its architecture.
- The 8085 Microprocessor is described as the foundational technology that paved the way for more advanced processors like Intel i7, i9, and Apple's M2 chip.
Architecture Overview:
- The architecture includes various registers and units, such as:
  - General Purpose Registers: Used for temporary data storage.
  - Flag Register: Indicates the status of operations (e.g., zero, carry).
  - Arithmetic Logic Unit (ALU): Performs arithmetic and logical operations.
  - Timing and Control Unit: Generates timing signals for operations.
Working Mechanism:
- The speaker explains the step-by-step process of instruction execution, including:
  - Program Counter: Holds the address of the next instruction to be executed.
  - Instruction Fetching: The process of retrieving instructions from memory.
  - Decoding Instructions: Understanding what the fetched instruction means (e.g., addition).
  - Execution of Instructions: Performing the operation as per the decoded instruction.
Example of Instruction Execution:
- An example is provided where two numbers are added:
  - Values are moved to the accumulator.
  - The addition operation is performed.
  - The result is stored back in memory or registers.
Stack Operations:
- The concept of a stack is introduced, explaining how values are pushed and popped from the stack:
  - Push Operation: Adds a value to the top of the stack.
  - Pop Operation: Removes the last value added to the stack.
Future Topics:
- The speaker indicates that the next video will cover the function of the Flag Register, detailing its significance in indicating the status of operations.

Methodology/Instructions:

Step-by-Step Execution of Instructions:
- Read the instruction from the Program Counter.
- Fetch the instruction from memory.
- Decode the instruction to understand the operation.
- Execute the operation using the ALU and store the result in the appropriate register or memory location.
Stack Operations:
- To Push a value:
  1. Place the value on top of the stack.
  2. Decrement the stack pointer.
- To Pop a value:
  1. Increment the stack pointer.
  2. Retrieve the value from the top of the stack.