8085 MICROPROCESSORS

 The 8085 microprocessor is an 8-bit microprocessor developed by Intel in the mid-1970s. It is a predecessor to the 8086 microprocessor and is part of the 8080/8085 family of processors.

Here are some key features and characteristics of the 8085 microprocessor:

1. Architecture: The 8085 microprocessor follows the simple instruction set computer (SISC) architecture. It has an 8-bit data bus, 16-bit address bus, and operates on 8-bit registers. The instruction set includes a range of instructions for arithmetic, logic, data movement, and control operations.

2. Memory Organization: The 8085 microprocessor can address up to 64 KB of memory. It supports a segmented memory model with separate memory banks for code and data.

3. Registers: The 8085 microprocessor has several important registers, including:

   - Accumulator (A): 8-bit register used for arithmetic and logic operations.

   - General-purpose registers: B, C, D, E, H, and L. These registers can be used individually or in pairs to perform operations on 16-bit data.

   - Stack Pointer (SP): Points to the top of the stack in memory.

   - Program Counter (PC): Holds the address of the next instruction to be fetched and executed.

4. Modes of Operation: The 8085 supports two primary modes of operation: single instruction execution mode and instruction fetch and execution mode. In single instruction execution mode, the processor executes a single instruction before waiting for the next instruction. In instruction fetch and execution mode, the processor fetches and executes instructions continuously.

5. Interrupts and Interrupt Handling: The 8085 has a built-in interrupt system to handle interrupt requests from external devices. It supports five types of interrupts: TRAP, RST 7.5, RST 6.5, RST 5.5, and INTR. Interrupts can be enabled or disabled using specific instructions, and the processor responds to the highest priority interrupt request.

6. Instruction Set: The 8085 instruction set includes a variety of instructions for arithmetic and logical operations, data movement, control flow, and I/O operations. It supports both immediate and memory operands and provides instructions for branching, looping, subroutine calls, and stack manipulation.

The 8085 microprocessor played a significant role in early microcomputer systems and was widely used in various applications such as embedded systems, industrial control, and educational environments. Its simple architecture, reasonable performance, and availability of development tools made it popular among hobbyists and professionals alike.