The instructions are the "language" of the processor. Gaonkar classifies them into functional categories. Data Transfer Instructions
Program Counter (PC): A 16-bit register that points to the next instruction address.
The 8085 interfaces with EPROM (for program storage) and RAM (for temporary data). Decoders like the 74LS138 are often used to map specific addresses to these chips. I/O Interfacing Peripheral-Mapped I/O: Uses IN and OUT instructions. Memory-Mapped I/O: Treats I/O devices as memory locations. Why Gaonkar's Approach? microprocessor 8085 ppt by gaonkar
The Intel 8085 is a landmark in the history of computing. Developed as an enhancement of the 8080, it became the foundation for teaching computer architecture. This guide follows the curriculum and structural style popularized by Ramesh Gaonkar, the leading authority on 8085 instruction and interfacing. Introduction to the 8085 Microprocessor
IO/M: Distinguishes between I/O operations and Memory operations. Interrupts The instructions are the "language" of the processor
The architecture is divided into several functional units that work in sync to execute instructions. The Arithmetic Logic Unit (ALU)
Stack Pointer (SP): A 16-bit register that manages the stack memory. Flag Register The 8085 interfaces with EPROM (for program storage)
AD0–AD7: Multiplexed address/data lines. This saves pins by using the same lines for the lower 8 bits of the address and the 8-bit data. A8–A15: Higher-order address lines. Control and Status Signals
The power of the 8085 lies in its ability to interact with the outside world. Memory Interfacing
RD and WR: Active low signals for reading and writing operations.