research paper on 8085

Don't have an account? Create new

Welcome to the Referral Program by IJIRT (International Journal of Innovative Research in Technology)!

Are you passionate about research and innovation join our referral program and become a valuable part of our community. here's how it works:, 1. register as a referral/reviewer:.

Sign up for our referral system by filling out a simple registration form. Once submitted, your registration awaits approval from the IJIRT Team.

2. Start Submitting Papers:

Gain access to our platform and begin submitting research papers for publication in our esteemed journal. Share your groundbreaking work with the world!

3. Earn Rewards:

After successfully processing the fee for your accepted research paper, you earn INR 800 as a token of appreciation for your contribution to academic excellence. Your dedication to advancing knowledge is rewarded!

4. Share Bank Details:

To start withdrawing your earnings, simply share your bank details with the IJIRT Team. We ensure secure transactions for all our agents.

5. Withdraw Your Earnings:

Now comes the exciting part! You can withdraw your hard-earned money earned by referring papers. However, there's a small twist. We have a locking amount of INR 1000. This means you can withdraw any amount exceeding INR 1000 at any given time. For example, if you've earned INR 5000, you can withdraw INR 4000, leaving INR 1000 as the locking amount.

Join us today and be a part of our mission to foster innovation and research excellence!

A specification of the intel 8085 microprocessor: A case study

• Part III Rapid Prototyping With Algebraic Specification
• Conference paper
• First Online: 01 January 2005
• Cite this conference paper

• Alfons Geser 1  

Part of the book series: Lecture Notes in Computer Science ((LNCS,volume 394))

Included in the following conference series:

• Workshop on Algebraic Methods

213 Accesses

4 Citations

As an instance for a large specification, an algebraic specification of the intel 8085 micro-processor is given. The specification is based on the concepts of hierarchical abstract types and conditional equations. With the help of the specification interpreter RAP, the specification is validated against some of its informal requirements. In the design of large software systems, a number of informal specification properties have to be considered such as style, readability, and structuredness of a specification. These properties are talked about using a couple of small examples.

intel is a registered trademark of intel Corporation, Santa Clara, CA.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Institutional subscriptions

Unable to display preview.  Download preview PDF.

R. Berghammer, H. Ehler, H. Zierer: Towards an algebraic specification of code generation . Report TUM-I8707, Technische Universität München, June 1987.

Google Scholar  

J. A. Bergstra, J. Heering, P. Klint: Algebraic Definition of a Simple Programming Language . Report CS-R8504, CWI, Amsterdam, Feb. 1985.

M. Broy: Specification and Top Down Design of Distributed Systems . Report MIP-8401, Universität Passau, Dec. 1984, MET. METEOR working paper

M. Broy: An Example for the Design of Distributed Systems in a Formal Setting: The Life Problem . Report MIP-8802, Universität Passau, Feb. 1988

A. Horsch, B. Möller, H. Partsch, O. Paukner, P. Pepper: The Munich Project CIP, Vol. II: The Program Transformation System CIP-S, Part I: Formal Specification . Lecture Notes in Computer Science 292, 1987.

L. M. G. Feijs, H. B. M. Jonkers, C. P. J. Koymans, G. R. Renardel de Lavalette: Formal Definition of the Design Language COLD-K . Technical Report, Philips Research Labs., Eindhoven, 1988, MET. METEOR working paper

J. H. A. Gelissen: Rapid Prototyping of COLD Specifications using RAP . Technical Report, Philips Research Labs., Eindhoven, April 1988, MET. METEOR working paper

A. Geser: A Specification of the intel 8085 Microprocessor: A Case Study . Report MIP-8608, Universität Passau, May 1986, MET. METEOR working paper

A. Geser, H. Hußmann: Rapid Prototyping for Algebraic Specifications — Examples for the Use of the RAP System . Report MIP-8517, Universität Passau, Dec. 1985, MET. METEOR working paper Updated version to appear.

A. Geser, H. Hußmann: Experiences with the RAP system — A Specification Interpreter combining Term Rewriting and Resolution . In: Proc. ESOP 86 Conf., March 1986, LNCS Lecture Notes in Computer Science 213, also as MET. METEOR working paper

A. Geser, H. Hußmann: A Compiler for a Class of Conditional Rewrite Systems . In: Proc. 1st Workshop on Conditional Rewriting, June 1987, LNCS Lecture Notes in Computer Science 308, pp. 84–90.

C. A. R. Hoare: Notes on Communicating Sequential Processes . Technical Monograph PRG-33, Oxford, Aug. 1983.

G. Huet, D. C. Oppen: Equations and Rewrite Rules — A Survey . In: R. V. Book (ed.): Formal Language Theory — Perspectives and Open Problems . Academic Press, 1980.

J. M. Hullot: Canonical Forms and Unification . Proc. 5th CADE Conf., LNCS Lecture Notes in Computer Science 87, pp. 318–334, 1980.

H. Hußmann: Unification in Conditional-Equational Theories . Report MIP-8502, Universität Passau, Passau 1985. Short version also in: Proc. EUROCAL 85 Conf., Vol. 2, LNCS 204, pp. 543–553, April 1985.

H. Hußmann: Rapid Prototyping for Algebraic Specifications — RAP System User's Manual (Second Edition) . Report MIP-8504, Universität Passau, Feb. 1987.

H. Hußmann, A. Geser: The RAP system as a tool for testing COLD specifications . In this volume.

H. Hußmann, C. Rank: Specification and Prototyping of a Compiler for a Small Applicative Language . In this volume.

Intel Corporation: 8080/8085 Assembly Language Programming . Santa Clara, 1979.

Intel Corporation: The MCS-80/85 Family User's Manual . Santa Clara, 1983.

K. E. Iverson: Programming in Systems Design . IBM Systems Journal, Vol. 2, June 1963, pp. 117–128.

H. B. M. Jonkers: An Introduction to COLD-K . Technical Report, Philips Research Labs., Eindhoven, July 1988.

S. Kaplan: A Compiler for Conditional Term Rewriting Systems . Proc. RTA 87 Conf., LNCS 256, pp. 25–41, May 1987.

L. Lavazza, S. Crespi-Reghizzi: Algebraic ADT Specifications of an Extended Relational Algebra and their Conversion into a Working Prototype . To appear as MET. METEOR working paper

P. Padawitz: ECDS — A Rewrite Rule Based Interpreter for a Programming Language with Abstraction and Communication . Report MIP-8703, Universität Passau, Feb. 1987, MET. METEOR working paper

P. Padawitz: Computing in Horn Clause Theories . EATCS Monographs in Theoretical Computer Science Vol. 16, 1988.

H. J. Sint: A Survey of High Level Microprogramming Languages . Proc. 13th Annual Workshop on Microprogramming, 1980.

M. Wirsing, P. Pepper, H. Partsch, W. Dosch, M. Broy: On Hierarchies of Abstract Data Types . Acta Informatica 20, pp. 1–33, 1983.

Article   Google Scholar  

M. Wirsing: Structured Algebraic Specifications: A Kernel Language . Habilitation Thesis, Technische Universitaet Muenchen, 1983. also as: Report MIP-8511, Universitaet Passau, 1985, MET. METEOR working paper also in Theoretical Computer Science.

A. Tarlezki, M. Wirsing: Continuous Abstract Types . In: Proc. MFCS 86, LNCS Lecture Notes in Computer Science 233, 1986, MET. METEOR working paper

Download references

Author information

Authors and affiliations.

Fakultät für Mathematik und Informatik, Universität Passau, Postfach 2540, D-8390, Passau

Alfons Geser

You can also search for this author in PubMed   Google Scholar

Editor information

Rights and permissions.

Reprints and permissions

Copyright information

© 1989 Springer-Verlag Berlin Heidelberg

About this paper

Cite this paper.

Geser, A. (1989). A specification of the intel 8085 microprocessor: A case study. In: Wirsing, M., Bergstra, J.A. (eds) Algebraic Methods: Theory, Tools and Applications. Algebraic Methods 1987. Lecture Notes in Computer Science, vol 394. Springer, Berlin, Heidelberg. https://doi.org/10.1007/BFb0015045

Download citation

DOI : https://doi.org/10.1007/BFb0015045

Published : 23 June 2005

Publisher Name : Springer, Berlin, Heidelberg

Print ISBN : 978-3-540-51698-9

Online ISBN : 978-3-540-46758-8

eBook Packages : Springer Book Archive

Share this paper

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Publish with us

Policies and ethics

• Find a journal
• Track your research

• Corpus ID: 61043731

Microprocessor architecture, programming, and applications with the 8085/8080A

• Published 1 March 1989
• Computer Science, Engineering

37 Citations

Simple 8085 microprocessor compatible i/o card, avr development board, design of components for a generic microprocessor architecture, design of a 16 bit risc processor, development of web-based 8085 microprocessor simulator and its implementation on lms, fpga based implementation of 16 bit risc microcontroller, design and development of advanced cross assembler for 8085 microprocessor, overview of interfacing data converters with 8085 microprocessor and its application, msp in digital system design, the use of java to develop a microprocessor emulator, related papers.

Showing 1 through 3 of 0 Related Papers

IEEE Account

• Change Username/Password
• Update Address

Purchase Details

• Payment Options
• Order History
• View Purchased Documents

Profile Information

• Communications Preferences
• Profession and Education
• Technical Interests
• US & Canada: +1 800 678 4333
• Worldwide: +1 732 981 0060
• Contact & Support
• About IEEE Xplore
• Accessibility
• Terms of Use
• Nondiscrimination Policy
• Privacy & Opting Out of Cookies

A not-for-profit organization, IEEE is the world's largest technical professional organization dedicated to advancing technology for the benefit of humanity. © Copyright 2024 IEEE - All rights reserved. Use of this web site signifies your agreement to the terms and conditions.

(Stanford users can avoid this Captcha by logging in.)

• Send to text email RefWorks EndNote printer

The 8085 microprocessor : architecture, programming and interfacing

Available online.

• Safari Books Online

More options

• Find it at other libraries via WorldCat
• Contributors

Description

Creators/contributors, contents/summary.

• Part I: Fundamentals of a Microprocessor
• Chapter 1: Evolution of Microprocessors
• 1.1 Early Integrated Circuits
• 1.2 4-Bit Microprocessors
• 1.3 8-Bit Microprocessors
• 1.4 16-Bit Microprocessors
• 1.5 32-Bit Microprocessors
• 1.6 Recent Microprocessors
• 1.7 Microcontrollers and Digital Signal Processors
• Chapter 2: Fundamentals of a Computer
• 2.1 Calculator
• 2.2 Computer
• 2.3 Microcomputer
• 2.4 Computer Languages
• Chapter 3: Number Representation
• 3.1 Unsigned Binary Integers
• 3.2 Signed Binary Integers
• 3.3 Representation of Fractions
• 3.4 Signed Floating Point Numbers
• Chapter 4: Fundamentals of Microprocessor
• 4.1 History of Microprocessors
• 4.2 Description of 8085 Pins
• 4.3 Programmer's View of 8085: Need for Registers
• 4.4 Accumulator or Register A
• 4.5 Registers B, C, D, E, H, And L
• Chapter 5: First Assembly Language Program
• 5.1 Problem Statement
• 5.2 About the Microprocessor Kit
• 5.3 Using the Microprocessor Kit in Serial Mode
• Chapter 6: Data Transfer Group of Instructions
• 6.1 Classification of 8085 Instructions
• 6.2 Instruction Type MVI r, d8
• 6.3 Instruction Type MOV r1, r2
• 6.4 Instruction Type MOV r, M
• 6.5 Instruction Type MOV M, r
• 6.6 Instruction Type LXI rp, d16
• 6.7 Instruction Type MVI m, d8
• 6.8 Instruction Type LDA a16
• 6.9 Instruction Type STA a16
• 6.10 Instruction Type XCHG
• 6.11 Addressing Modes of 8085
• 6.12 Instruction Type LDAX rp
• 6.13 Instruction Type STAX rp
• 6.14 Instruction Type LHLD a16
• 6.15 Instruction Type SHLD a16
• Chapter 7: Arithmetic Group of Instructions
• 7.1 Instructions to Perform Addition
• 7.2 Instructions to Perform Subtraction
• 7.3 Instruction Type INX rp
• 7.4 Instruction Type DCX rp.
• 7.5 Instruction Type DAD rp
• 7.6 Decimal Addition in 8085
• Chapter 8: Logical Group of Instructions
• 8.1 Instructions to Perform 'AND' Operation
• 8.2 Instructions to Perform 'OR' Operation
• 8.3 Instructions to Perform 'EXCLUSIVE OR' Operation
• 8.4 Instruction to Complement Accumulator
• 8.5 Instructions to Complement/Set 'Cy' Flag
• 8.6 Instructions to Perform Compare Operation
• 8.7 Instructions to Rotate Accumulator
• Chapter 9: NOP and Stack Group of Instructions
• 9.1 Stack and The Stack Pointer
• 9.2 Instruction Type POP rp
• 9.3 Instruction Type PUSH rp
• 9.4 Instruction Type LXI SP, d16
• 9.5 Instruction Type SPHL
• 9.6 Instruction Type XTHL
• 9.7 Instruction Type INX SP
• 9.8 Instruction Type DCX SP
• 9.9 Instruction Type DAD SP
• 9.10 Instruction Type NOP
• Chapter 10: Branch Group of Instructions
• 10.1 More Details about Program Execution
• 10.2 Unconditional Jump Instructions
• 10.3 Conditional Jump Instructions
• 10.4 Unconditional Call and Return Instructions
• 10.5 Conditional Call Instructions
• 10.6 Conditional Return Instructions
• Restart Instructions
• Chapter 11: Chip Select Logic
• 11.1 Concept of Chip Selection
• 11.2 RAM Chip-Pin Details and Address Range
• 11.3 Multiple Memory Address Range
• 11.4 Working of 74138 Decoder IC
• 11.5 Use of 74138 to Generate Chip Select Logic
• 11.6 Use of 74138 in ALS-SDA-85M Kit
• Chapter 12: Addressing of I/O Ports
• 12.1 Need for I/O Ports
• 12.2 IN and OUT Instructions
• 12.3 Memory-Mapped I/O
• 12.4 I/O-Mapped I/O
• 12.5 Comparison of Memory-Mapped I/O and I/O-Mapped I/O
• Chapter 13: Architecture of 8085
• 13.1 Details of 8085 Architecture
• 13.2 Instruction Cycle
• 13.3 Comparison of Different Machine Cycles
• 13.4 Memory Speed Requirement.
• 13.5 Wait State Generation
• Part II: Assembly Language Programs
• Chapter 14: Simple Assembly Language Programs
• 14.1 Exchange 10 Bytes
• 14.2 Add two Multi-Byte Numbers
• 14.3 Add two Multi-Byte BCD Numbers
• 14.4 Block Movement without Overlap
• 14.5 Block Movement with Overlap
• 14.6 Add N Numbers of Size 8 Bits
• 14.7 Check the Fourth Bit of a Byte
• 14.8 Subtract two Multi-Byte Numbers
• 14.9 Multiply two numbers of Size 8 Bits
• 14.10 Divide a 16-Bit Number by an 8-Bit Number
• Chapter 15: Use of PC in Writing and Executing 8085 Programs
• 15.1 Steps Needed to Run an Assembly Language Program
• 15.2 Creation of .ASM File using a Text Editor
• 15.3 Generation of .OBJ File using a Cross-Assembler
• 15.4 Generation of .HEX File using a Linker
• 15.5 Downloading the Machine Code to the Kit
• 15.6 Running the Downloaded Program on the Kit
• 15.7 Running the Program using the PC as a Terminal
• Chapter 16: Additional Assembly Language Programs
• 16.1 Search for a Number using Linear Search
• 16.2 Find the Smallest Number
• 16.3 Compute the HCF of Two 8-Bit Numbers
• 16.4 Check for '2 out of 5' Code
• 16.5 Convert ASCII to Binary
• 16.6 Convert Binary to ASCII
• 16.7 Convert BCD to Binary
• 16.8 Convert Binary to BCD
• 16.9 Check for Palindrome
• 16.10 Compute the LCM of Two 8-Bit Numbers
• 16.11 Sort Numbers using Bubble Sort
• 16.12 Sort Numbers using Selection Sort
• 16.13 Simulate Decimal up Counter
• 16.14 Simulate Decimal down Counter
• 16.15 Display Alternately 00 and FF in the Data Field
• 16.16 Simulate a Real-Time Clock
• Chapter 17: More Complex Assembly Language Programs
• 17.1 Subtract Multi-Byte BCD Numbers
• 17.2 Convert 16-Bit Binary to BCD
• 17.3 Do an operation on Two Numbers Based on the Value of X.
• 17.4 Do an Operation on Two BCD Numbers Based on the Value of X
• 17.5 Bubble Sort in Ascending/Descending Order as per Choice
• 17.6 Selection Sort in Ascending/Descending Order as per Choice
• 17.7 Add Contents of N Word Locations
• 17.8 Multiply Two 8-Bit Numbers (Shift and Add Method)
• 17.9 Multiply two 2-Digit BCD Numbers
• 17.10 Multiply two 16-Bit Binary Numbers
• Part III: Programmable and Non-Programmable I/O Ports
• Chapter 18: Interrupts in 8085
• 18.1 Data Transfer Schemes
• 18.2 General Discussion about 8085 Interrupts
• 18.3 EI and DI Instructions
• 18.4 INTR and INTA* Pins
• 18.5 RST5.5 and RST6.5 Pins
• 18.6 RST7.5 Pin
• 18.7 Trap Interrupt Pin
• 18.8 Execution of 'DAD rp' Instruction
• 18.9 SIM and RIM Instructions
• 18.10 HLT Instruction
• 18.11 Programs using Interrupts
• Chapter 19: 8212 Non-Programmable8-Bit I/O Port
• 19.1 Working of 8212
• 19.2 Applications of 8212
• Chapter 20: 8255 Programmable Peripheral Interface Chip
• 20.1 Description of 8255 PPI
• 20.2 Operational Modes of 8255
• 20.3 Control Port of 8255
• 20.4 Mode 1-Strobed I/O
• 20.5 Mode 2-Bi-Directional I/O
• Chapter 21: Programs using Interface Modules
• 21.1 Description of Logic Controller Interface
• 21.2 Successive Approximation ADC Interface
• 21.3 Dual Slope ADC Interface
• 21.4 Digital to Analog Converter Interface
• 21.5 Stepper Motor Interface
• Part IV: Support Chips
• Chapter 22: Interfacing of I/O Devices
• 22.1 Interfacing 7-Segment Display
• 22.2 Display Interface using Serial Transfer
• 22.3 Interfacing a Simple Keyboard
• 22.4 Interfacing a Matrix Keyboard
• 22.5 Description of Matrix Keyboard Interface
• 22.6 Intel 8279 Keyboard And Display Controller
• 22.7 Programs using 8279
• Chapter 23: Intel 8259A-Programmable Interrupt Controller
• 23.1 Need for an Interrupt Controller
• 23.2 Overview of the Working of 8259
• 23.3 Pins of 8259
• 23.4 Registers used in 8259
• 23.5 Programming the 8259 with no Slaves
• 23.6 Programming the 8259 with Slaves
• 23.7 Use of 8259 in an 8086-Based System
• 23.8 Architecture of 8259
• Chapter 24: Intel 8257-Programmable DMA Controller
• 24.1 Concept of Direct Memory Access (DMA)
• 24.2 Need for DMA Data Transfer
• 24.3 Description of 8257 DMA Controller Chip
• 24.4 Programming the 8257
• 24.5 Description of the Pins Of 8257
• 24.6 Working of the 8257 DMA Controller
• 24.7 State Diagram of 8085
• Chapter 25: Intel 8253-Programmable Interval Timer
• 25.1 Need for Programmable Interval Timer
• 25.2 Description of 8253 Timer
• 25.3 Programming the 8253
• 25.4 Mode 0-Interrupt On Terminal Count
• 25.5 Mode 1-Re-Triggerable Mono- Stable Multi
• 25.6 Mode 2-Rate Generator
• 25.7 Mode 3-Square Wave Generator
• 25.8 Mode 4-Software-Triggered Strobe
• 28.9 Mode 5-Hardware-Triggered Strobe
• 28.10 Use of 8253 in ALS-SDA-85 Kit
• Chapter 26: Intel 8251A-Universal Synchronous Asynchronous Receiver Transmitter (USART)
• 26.1 Need for USART
• 26.2 Asynchronous Transmission
• 26.3 Asynchronous Reception
• 26.4 Synchronous Transmission
• 26.5 Synchronous Reception
• 26.6 Pin Description of 8251 USART
• 26.7 Programming the 8251
• 26.8 Use of SOD Pin of 8085 for Serial Transfer
• Chapter 27: Zilog Z-80 Microprocessor
• 27.1 Comparison of Intel 8080 with Intel 8085
• 27.2 Programmer's View of Z-80
• 27.3 Special Features of Z-80
• 27.4 Addressing Modes of Z-80
• 27.5 Special Instruction Types
• 27.6 Pins of Z-80
• 27.7 Interrupt Structure in Z-80
• 27.8 Programming Examples
• 27.9 Instruction Set Summary

Bibliographic information

Browse related items.

• Stanford Home
• Maps & Directions
• Search Stanford
• Emergency Info
• Terms of Use
• Non-Discrimination
• Accessibility

© Stanford University , Stanford , California 94305 .

• Java for Android
• Android Studio
• Android Kotlin
• Android Project
• Android Interview

Architecture of 8085 microprocessor

Introduction :

The 8085 microprocessor is an 8-bit microprocessor that was developed by Intel in the mid-1970s . It was widely used in the early days of personal computing and was a popular choice for hobbyists and enthusiasts due to its simplicity and ease of use. The architecture of the 8085 microprocessor consists of several key components, including the accumulator, registers, program counter, stack pointer, instruction register, flags register, data bus, address bus, and control bus.

The accumulator is an 8-bit register that is used to store arithmetic and logical results. It is the most commonly used register in the 8085 microprocessor and is used to perform arithmetic and logical operations such as addition, subtraction, and bitwise operations.

The 8085 microprocessor has six general-purpose registers, including B, C, D, E, H, and L, which can be combined to form 16-bit register pairs. The B and C registers can be combined to form the BC register pair, the D and E registers can be combined to form the DE register pair, and the H and L registers can be combined to form the HL register pair. These register pairs are commonly used to store memory addresses and other data.

The program counter is a 16-bit register that contains the memory address of the next instruction to be executed. The program counter is incremented after each instruction is executed, which allows the microprocessor to execute instructions in sequence.

The stack pointer is a 16-bit register that is used to manage the stack. The stack is a section of memory that is used to store data temporarily, such as subroutine addresses and other data. The stack pointer is used to keep track of the top of the stack.

The instruction register is an 8-bit register that contains the current instruction being executed. The instruction register is used by the microprocessor to decode and execute instructions.

The flags register is an 8-bit register that contains status flags that indicate the result of an arithmetic or logical operation. These flags include the carry flag, zero flag, sign flag, and parity flag. The carry flag is set when an arithmetic operation generates a carry, the zero flag is set when the result of an arithmetic or logical operation is zero, the sign flag is set when the result of an arithmetic or logical operation is negative, and the parity flag is set when the result of an arithmetic or logical operation has an even number of 1 bits.

The data bus is an 8-bit bus that is used to transfer data between the microprocessor and memory or other devices. The data bus is bidirectional, which means that it can be used to read data from memory or write data to memory.

The address bus is a 16-bit bus that is used to address memory and other devices. The address bus is used to select the memory location or device that the microprocessor wants to access.

The control bus is a set of signals that controls the operations of the microprocessor, including the read and write operations. The control bus includes signals such as the read signal, write signal, interrupt signal, and reset signal. The read signal is used to read data from memory or other devices, the write signal is used to write data to memory or other devices, the interrupt signal is used to signal the microprocessor that an interrupt has occurred, and the reset signal is used to reset the microprocessor to its initial state.

8085 is an 8-bit, general-purpose microprocessor. It consists of the following functional units:

Arithmetic and Logic Unit (ALU) :

It is used to perform mathematical operations like addition, multiplication, subtraction, division, decrement, increment, etc. Different operations are carried out in ALU: Logical operations, Bit-Shifting Operations, and Arithmetic Operations.  

Flag Register:

It is an 8-bit register that stores either 0 or 1 depending upon which value is stored in the accumulator.  Flag Register contains 8-bit out of which 5-bits are important and the rest of 3-bits are “don’t Care conditions”. The flag register is a dynamic register because after each operation to check whether the result is zero, positive or negative, whether there is any overflow occurred or not, or for comparison of two 8-bit numbers carry flag is checked. So for numerous operations to check the contents of the accumulator and from that contents if we want to check the behavior of given result then we can use Flag register to verify and check. So we can say that the flag register is a status register and it is used to check the status of the current operation which is being carried out by ALU.

Different Fields of Flag Register:

• Parity Flag
• Auxiliary Carry Flag

Accumulator:

Accumulator is used to perform I/O, arithmetic, and logical operations. It is connected to ALU and the internal data bus. The accumulator is the heart of the microprocessor because for all arithmetic operations Accumulator’s 8-bit pin will always there connected with ALU and in most-off times all the operations carried by different instructions will be stored in the accumulator after operation performance.

General Purpose Registers:

There are six general-purpose registers. These registers can hold 8-bit values. These  8-bit registers are B,C,D,E,H,L. These registers work as 16-bit registers when they work in pairs like B-C, D-E, and H-L. Here registers W and Z are reserved registers. We can’t use these registers in arithmetic operations. It is reserved for microprocessors for internal operations like swapping two 16-bit numbers. We know that to swap two numbers we need a third variable hence here W-Z register pair works as temporary registers and we can swap two 16-bit numbers using this pair.

Program Counter : 

Program Counter holds the address value of the memory to the next instruction that is to be executed. It is a 16-bit register.

For Example: Suppose current value of Program Counter : [PC] = 4000H (It means that next executing instruction is at location 4000H.After fetching,program Counter(PC) always increments  by +1 for fetching of next instruction.)  

Stack Pointer :

It works like a stack. In stack, the content of the register is stored that is later used in the program. It is a 16-bit special register. The stack pointer is part of memory but it is part of Stack operations, unlike random memory access. Stack pointer works in a continuous and contiguous part of the memory. whereas Program Counter(PC) works in random memory locations. This pointer is very useful in stack-related operations like PUSH, POP, and nested CALL requests initiated by Microprocessor. It reserves the address of the most recent stack entry.

Temporary Register:

It is an 8-bit register that holds data values during arithmetic and logical operations.

Instruction register and decoder:

It is an 8-bit register that holds the instruction code that is being decoded. The instruction is fetched from the memory. 

Timing and control unit:

The timing and control unit comes under the CPU section, and it controls the flow of data from the CPU to other devices. It is also used to control the operations performed by the microprocessor and the devices connected to it. There are certain timing and control signals like Control signals, DMA Signals, RESET signals and Status signals. 

Interrupt control:

Whenever a microprocessor is executing the main program and if suddenly an interrupt occurs, the microprocessor shifts the control from the main program to process the incoming request. After the request is completed, the control goes back to the main program. There are 5 interrupt signals in 8085 microprocessors: INTR, TRAP, RST 7.5, RST 6.5, and RST 5.5.

Priorities of Interrupts: TRAP > RST 7.5 > RST 6.5 > RST 5.5 > INTR

Address bus and data bus: 

The data bus is bidirectional and carries the data which is to be stored.  The address bus is unidirectional and carries the location where data is to be stored.

In the 8085 microprocessor, the address bus and data bus are two separate buses that are used for communication between the microprocessor and external devices.

The Address bus is used to transfer the memory address of the data that needs to be read or written. The address bus is a 16-bit bus, allowing the 8085 to access up to 65,536 memory locations.

The Data bus is used to transfer data between the microprocessor and external devices such as memory and I/O devices. The data bus is an 8-bit bus, allowing the 8085 to transfer 8-bit data at a time. The data bus can also be used for instruction fetch operations, where the microprocessor fetches the instruction code from memory and decodes it.

The combination of the address bus and data bus allows the 8085 to communicate with and control external devices, allowing it to execute its program and perform various operations.

Serial Input/output control:

It controls the serial data communication by using Serial input data and Serial output data.

Serial Input/Output control in the 8085 microprocessor refers to the communication of data between the microprocessor and external devices in a serial manner, i.e., one bit at a time. The 8085 has a serial I/O port (SID/SOD) for serial communication. The SID pin is used for serial input and the SOD pin is used for serial output. The timing and control of serial communication is managed by the 8085’s internal circuitry. The 8085 also has two special purpose registers, the Serial Control Register (SC) and the Serial Shift Register (SS), which are used to control and monitor the serial communication.

The flow of an Instruction Cycle in 8085 Architecture :

• Execution starts with Program Counter. It starts program execution with the next address field. it fetches an instruction from the memory location pointed by Program Counter.
• For address fetching from the memory, multiplexed address/data bus acts as an address bus and after fetching instruction this address bus will now acts as a data bus and extract data from the specified memory location and send this data on an 8-bit internal bus. For multiplexed address/data bus Address Latch Enable(ALE) Pin is used. If ALE = 1 (Multiplexed bus is Address Bus otherwise it acts as Data Bus).
• After data fetching data will go into the Instruction Register it will store data fetched from memory and now data is ready for decoding so for this Instruction decoder register is used.
• After that timing and control signal circuit comes into the picture. It sends control signals all over the microprocessor to tell the microprocessor whether the given instruction is for READ/WRITE and whether it is for MEMORY/I-O Device activity.
• Hence according to timing and control signal pins, logical and arithmetic operations are performed and according to that data fetching from the different registers is done by a microprocessor, and mathematical operation is carried out by ALU. And according to operations Flag register changes dynamically.
• With the help of Serial I/O data pin(SID or SOD Pins) we can send or receive input/output to external devices .in this way execution cycle is carried out.
• While execution is going on if there is any interrupt detected then it will stop execution of the current process and Invoke Interrupt Service Routine (ISR) Function. Which will stop the current execution and do execution of the current occurred interrupt after that normal execution will be performed.

Uses of 8085 microprocessor :

The 8085 microprocessor is a versatile 8-bit microprocessor that has been used in a wide variety of applications, including:

• Embedded Systems: The 8085 microprocessor is commonly used in embedded systems, such as industrial control systems, automotive electronics, and medical equipment.
• Computer Peripherals: The 8085 microprocessor has been used in a variety of computer peripherals, such as printers, scanners, and disk drives.
• Communication Systems: The 8085 microprocessor has been used in communication systems, such as modems and network interface cards.
• Instrumentation and Control Systems: The 8085 microprocessor is commonly used in instrumentation and control systems, such as temperature and pressure controllers.
• Home Appliances: The 8085 microprocessor is used in various home appliances, such as washing machines, refrigerators, and microwave ovens.
• Educational Purposes: The 8085 microprocessor is also used for educational purposes, as it is an inexpensive and easily accessible microprocessor that is widely used in universities and technical schools.

Issues in 8085 microprocessor :

Here are some common issues with the 8085 microprocessor:

• Overheating: The 8085 microprocessor can overheat if it is used for extended periods or if it is not cooled properly. Overheating can cause the microprocessor to malfunction or fail.
• Power Supply Issues: The 8085 microprocessor requires a stable power supply for proper operation. Power supply issues such as voltage fluctuations, spikes, or drops can cause the microprocessor to malfunction.
• Timing Issues: The 8085 microprocessor relies on accurate timing signals for proper operation. Timing issues such as clock signal instability, noise, or interference can cause the microprocessor to malfunction.
• Memory Interface Issues: The 8085 microprocessor communicates with memory through its address and data buses. Memory interface issues such as faulty memory chips, loose connections, or address decoding errors can cause the microprocessor to malfunction.
• Hardware Interface Issues: The 8085 microprocessor communicates with other devices through its input/output ports. Hardware interface issues such as faulty devices, incorrect wiring, or improper device selection can cause the microprocessor to malfunction.
• Programming Issues: The 8085 microprocessor is programmed with machine language or assembly language instructions. Programming issues such as syntax errors, logic errors, or incorrect instruction sequences can cause the microprocessor to malfunction or produce incorrect results.
• Research and development: The 8085 microprocessor is often used in research and development projects, where it can be used to develop and test new digital electronics and computer systems. Researchers and developers can use the microprocessor to prototype new systems and test their performance.
• Retro computing: The 8085 microprocessor is still used by enthusiasts today for retro computing projects. Retro computing involves using older computer systems and technologies to explore the history of computing and gain a deeper understanding of how modern computing systems have evolved.

Reference :

• “Microprocessor Architecture, Programming, and Applications with the 8085” by Ramesh S. Gaonkar – This book provides a comprehensive introduction to the architecture and programming of the 8085 microprocessor, along with examples and exercises.
• “The 8085 Microprocessor: Architecture, Programming and Interfacing” by Udaya Kumar – This book provides an in-depth treatment of the architecture, programming, and interfacing of the 8085 microprocessor, with numerous examples and exercises.
• “Introduction to Microprocessors and Microcontrollers” by John Crisp – This book provides an introduction to the architecture and programming of various microprocessors and microcontrollers, including the 8085.
• Intel 8085 Microprocessor Data Sheet – This is the official data sheet for the 8085 microprocessor, which provides detailed information on the architecture, instruction set, and programming of the microprocessor.
• Online resources such as tutorials, articles, and videos are also available on websites like tutorialspoint.com, electronicsforu.com, and YouTube.

Please Login to comment...

Similar reads.

• Computer Organization & Architecture
• CSS-Functions
• Intellipaat
• Java-SecureRandom
• microprocessor
• permutation
• Python numpy-Random
• python-dict
• QA - Placement Quizzes-Data Interpretation
• R Graphics-Functions
• TCS-coding-questions
• Best PS5 SSDs in 2024: Top Picks for Expanding Your Storage
• Best Nintendo Switch Controllers in 2024
• Xbox Game Pass Ultimate: Features, Benefits, and Pricing in 2024
• Xbox Game Pass vs. Xbox Game Pass Ultimate: Which is Right for You?
• Full Stack Developer Roadmap [2024 Updated]

Improve your Coding Skills with Practice

What kind of Experience do you want to share?

Academia.edu no longer supports Internet Explorer.

To browse Academia.edu and the wider internet faster and more securely, please take a few seconds to  upgrade your browser .

Enter the email address you signed up with and we'll email you a reset link.

• We're Hiring!
• Help Center

Tutorial On Introduction to 8085 Architecture and Programming Contents

Related Papers

ANURUDH KASHYA

Jose Edavoor

Microprocessor 8085 basics and simple programs

Loading Preview

Sorry, preview is currently unavailable. You can download the paper by clicking the button above.

RELATED TOPICS

•   We're Hiring!
•   Help Center
• Find new research papers in:
• Health Sciences
• Earth Sciences
• Cognitive Science
• Mathematics
• Computer Science
• Academia ©2024

Publications by Topics

Explore science topics to find research in your field such as publications, questions, research projects, and methods.

• Recruit researchers
• Join for free
• Login Email Tip: Most researchers use their institutional email address as their ResearchGate login Password Forgot password? Keep me logged in Log in or Continue with Google Welcome back! Please log in. Email · Hint Tip: Most researchers use their institutional email address as their ResearchGate login Password Forgot password? Keep me logged in Log in or Continue with Google No account? Sign up