R. Gaonkar Microprocessor Architecture Programming And Applications With The 8085 Prentice Hall 2014 Site

Perhaps the most practical section of the text is Part III: Interfacing. This is where the rubber meets the road. Gaonkar explains how to connect the CPU to the outside world.

This section is crucial for students moving into Embedded Systems. It teaches that hardware is useless without the software driver to control it, and software is abstract without the hardware to run it.

When the 2014 edition was released, the world was already using Intel Core i7 processors. However, the 8085 (introduced by Intel in 1977) remains the ideal teaching tool for several compelling reasons: Perhaps the most practical section of the text

Gaonkar’s 2014 edition acknowledges that students will eventually move to ARM or x86, but it argues convincingly that understanding the 8085 first accelerates learning of any other architecture.

| Chapter | Title | Key Concepts | |---------|-------|----------------| | 1 | Microprocessor Evolution | 4004 → 8085 → x86; stored program concept | | 2 | 8085 Architecture | ALU, register array (BC, DE, HL, SP, PC), flag register, internal bus | | 3 | 8085 Pin Description & Timing | Multiplexed AD0–AD7, A8–A15; RD, WR, IO/M, clock; machine cycle/state | | 4 | Programming Fundamentals | Opcode/operand; addressing modes (immediate, register, direct, indirect, implicit) | | 5 | Instruction Set Classification | Data transfer, arithmetic, logical, branch, stack/machine control | | 6 | Assembly Language Programming | Structure of assembly program; labels, directives (ORG, EQU, DB, DS) | | 7 | Counter & Time Delay | Loops; register pair as counter; using NOP & nested loops for delay | | 8 | Stack & Subroutines | PUSH/POP; CALL/RET; passing data via registers/memory | | 9 | Code Conversion & BCD/ASCII | Binary ↔ BCD; 7-segment; ASCII ↔ binary | | 10 | Interrupts | Vectored vs non-vectored; TRAP, RST 5.5, 6.5, 7.5; SIM/RIM | | 11 | Interfacing I/O Devices | Memory-mapped vs isolated I/O; 8255 PPI (mode 0, 1, 2) | | 12 | Advanced Interfacing | 8253/8254 (timer), 8279 (keyboard/display), 8259 (PIC) | | 13 | Applications | Traffic light controller; temperature monitor; stepper motor driver | This section is crucial for students moving into

Chapter 10-12: Interfacing Concepts – Gaonkar shines here. He explains:

Chapter 13: Interrupts – A deep dive into the 8085’s five interrupts (TRAP, RST 7.5, RST 6.5, RST 5.5, INTR). The 2014 edition includes modern equivalents like vectored interrupt controllers. source address MOV A

Chapter 14: Peripheral Interfacing – Practical examples with real chips:

LXI H, 3000H    ; source address
MOV A, M
INX H
ADD M
INX H
MOV M, A
HLT