8051 Microcontroller Subrata Ghoshal Pdf Download 'link' 〈Ultimate〉

The book " 8051 Microcontroller: Internals, Instructions, Programming and Interfacing

" by Subrata Ghoshal is a comprehensive guide widely used for academic and professional study of embedded systems. Published by Pearson Education, it spans 26 chapters and approximately 512 to 536 pages. Core Content Overview

The book is structured into four primary segments to guide students from basic architecture to complex system design:

Internal Architecture: Detailed analysis of the 8051's 8-bit CPU, including the ALU, memory organization (RAM and ROM), and registers like the Program Status Word (PSW).

Instruction Set and Programming: Comprehensive coverage of assembly language instructions with practical examples, data types (unsigned/signed char, int), and addressing modes.

Peripherals and Interrupts: In-depth discussion on timers/counters, serial communication, and the microcontroller's interrupt-handling features.

Interfacing and Applications: Techniques for connecting the 8051 to external devices such as: Motors (stepper, DC) and relays. Sensors, ADC/DAC converters, and memory devices. Keyboards, LEDs, and LCD displays. Key Features Understanding 8051 Microcontroller Basics | PDF - Scribd

8051 Microcontroller: Internals, Instructions, Programming & Interfacing by Subrata Ghoshal is a widely recognized academic resource for students and engineers diving into the world of embedded systems. First published in 2010 by Pearson Education, this book provides a comprehensive breakdown of the 8051 architecture through clear language and detailed graphical annotations. Book Overview and Content

The textbook is designed to bridge the gap between basic microprocessor theory and practical microcontroller application. It covers the entire lifecycle of learning the MCS-51 family:

Internal Architecture: Detailed exploration of the 8051's CPU, memory organization (RAM/ROM), and the difference between Princeton and Harvard architectures.

Instruction Set: A thorough guide to 8051 opcodes, including data movement (MOV, MOVX, MOVC) and logical operations.

Programming: Practical guidance on writing code for the 8051, with the second edition featuring expanded content on C language-based programming for modern applications.

Interfacing: Step-by-step instructions for connecting the microcontroller to external hardware like sensors, timers, and I/O devices. Key Technical Features of the 8051

Subrata Ghoshal’s text highlights the standard features that have made the 8051 a staple in industry and education for decades: 8051 Microcontroller By Subrata Ghoshal (S) - Amazon.in

Customer reviews. 4.8 out of 5 stars4.8 out of 5. 20 global ratings. Top review from India. There was a problem filtering reviews.

Internals, Instructions, Programming and Interfacing (Old Edition)

8051 Microcontroller: Internals, Instructions, Programming and Interfacing Subrata Ghoshal

is a comprehensive guide widely used by engineering students to understand the architecture and application of the 8051 family. Key Content Overview

The book is structured to take a learner from basic hardware concepts to complex peripheral interfacing. Major sections include: Microprocessor vs. Microcontroller

: A foundational comparison of CISC and RISC architectures and why the 8051 is a standard for embedded systems. 8051 Architecture

: Detailed breakdown of the CPU, Memory Organization (Internal RAM/ROM), Special Function Registers (SFRs), and the I/O port structure. Instruction Set

: Coverage of Data Transfer, Arithmetic, Logical, and Branching instructions with examples in Assembly Language C Programming for 8051 : Introduction to Embedded C

, explaining how to use compilers like Keil to write more efficient code than standard assembly. On-chip Peripherals

: Technical guidance on configuring and using internal Timers/Counters, Serial Communication (UART), and Interrupt handling. Interfacing

: Practical circuits and code for connecting the 8051 to external devices, including: Seven-segment displays and LCDs. Keyboards and Matrix switches. ADCs, DACs, and various Sensors. Stepper motors and DC motors. Where to Access

While I cannot provide a direct PDF download link for copyrighted material, you can access the content through these legitimate channels: Pearson Education : The official publisher's site often provides sample chapters or digital rentals Google Books : Offers a limited preview where you can read several chapters for free.

: Most university libraries carry physical or digital copies via platforms like or an example of 8051 Assembly code for a particular task?

Subrata Ghoshal 8051 Microcontroller: Internals, Instructions, Programming and Interfacing

is a comprehensive guide widely used in academic settings to teach the fundamentals of embedded systems. The book is known for its structured approach, using simple language and extensive graphical annotations to explain complex architecture and programming concepts. Key Features of the Book Comprehensive Architecture

: Detailed coverage of 8051 internal architecture, including its 8-bit data bus, 128 bytes of RAM, and 4KB of on-chip ROM. Programming & Interfacing

: Provides in-depth discussions on instruction sets, assembly language, and interfacing the 8051 with external devices like motors, sensors, keyboards, and displays. Classroom Oriented

: Each chapter follows a pedagogical structure: objectives, introduction, exposition with examples, summaries, and review questions. Modern Applications : The second edition includes additional content on C language programming for varied embedded applications. Specialized Topics

: Includes dedicated chapters on interrupt handling and power-saving schemes, which are critical for battery-powered systems. Access and Downloads

While direct "free" PDF downloads of copyrighted textbooks are often found on unofficial document-sharing sites, they may be of poor quality or infringe on copyrights. For legitimate access, you can find the book on the following platforms: Official Digital Versions : Available as a Kindle eBook or for digital preview on Google Books Institutional Access : Platforms like

provide access to the full text for those with academic or corporate subscriptions. Document Repositories : Sites like

host user-uploaded copies, though the quality can vary significantly. O'Reilly books Quick Technical Specs covered in the Text

1. Introduction to 8051 Microcontroller 2. Architecture of 8051

The textbook " 8051 Microcontroller: Internals, Instructions, Programming & Interfacing " by Subrata Ghoshal

is a widely used academic resource for understanding 8-bit microcontrollers. Published by Pearson Education, it covers the architecture, instruction set, and practical interfacing techniques for the 8051 family. Where to Access or Download

While downloading copyrighted textbooks for free is often restricted, you can find the book or related resources through these platforms:

Official Digital Preview: You can view portions of the book, including the table of contents and introductory chapters, on Google Books.

Document Repositories: PDF summaries, overview documents, or user-uploaded versions are sometimes available on Scribd or Dokumen.pub. Note that these sites often require a subscription or account.

Library and Academic Portals: Many university libraries provide access to the digital version via Pearson MyLab or institutional logins. Key Features of the Book

Architecture & Internals: Detailed breakdown of the Harvard architecture, 8051 pinout, and internal RAM/ROM organization. 8051 microcontroller subrata ghoshal pdf download

Programming: Comprehensive guide to both Assembly language and Embedded C programming.

Interfacing: Practical tutorials on connecting the 8051 to peripherals like 7-segment displays, LCDs, keyboards, and sensors.

Real-world Applications: Covers the use of 8051 in robotics, automotive systems, and industrial control. Why Study the 8051 Today?

Despite being developed in the 1980s, the 8051 remains relevant because:

Educational Foundation: Its simple architecture makes it the gold standard for learning microcontroller fundamentals.

Legacy Systems: Many industrial sectors still use 8051-based architectures due to their reliability and cost-effectiveness. Subrata Ghoshal Document Overview | PDF - Scribd

Introduction to 8051 Microcontroller

The 8051 microcontroller is an 8-bit microcontroller that was first introduced by Intel in 1980. It has become a widely used and popular microcontroller in many embedded systems and applications. The 8051 microcontroller is known for its simplicity, ease of use, and versatility.

Features of 8051 Microcontroller

The 8051 microcontroller has several key features that make it a popular choice:

Applications of 8051 Microcontroller

The 8051 microcontroller is widely used in various applications, including:

Programming 8051 Microcontroller

The 8051 microcontroller can be programmed using a variety of programming languages, including assembly language and C. The most common programming language used for the 8051 is Keil C.

If you're interested in learning more about the 8051 microcontroller, I recommend checking out the book by Subrata Ghoshal. You can try searching for the book on online platforms or visiting your local library.

Here are some online resources where you might be able to find the book or learn more about the 8051 microcontroller:

If you're looking for a free PDF download, I recommend checking out websites like:

Please note that downloading copyrighted materials without permission is illegal. Make sure to respect the author's and publisher's rights by purchasing a copy of the book or accessing it through legitimate channels.

The primary textbook for this topic is "8051 Microcontroller: Internals, Instructions, Programming and Interfacing" by Subrata Ghoshal, published by Pearson. It is widely used in undergraduate electronics and computer science programs to teach embedded system basics. Key Resources for Subrata Ghoshal's 8051 Material

While direct "free download" links for copyrighted textbooks are often restricted, you can find helpful summaries, digital notes, and legal previews on these platforms:

Study Previews: Platforms like Dokumen.pub provide detailed metadata and previews of the book's 483-page structure.

Lecture Slides & Summaries: You can access introductory summaries and technical slides that cite Ghoshal’s methods on Scribd and SlideShare.

Academic Digital Notes: For structured course notes based on this curriculum, universities like MRCET offer digital PDF notes covering 8051 architecture and interfacing. Helpful Technical Highlights (per the text)

Based on the curriculum typically covered by Subrata Ghoshal, here are the essential 8051 concepts:

The 8051 Microcontroller: A Comprehensive Guide by Subrata Ghoshal

The 8051 microcontroller is one of the most popular and widely used microcontrollers in the world. First introduced in 1980 by Intel, it has become a standard component in many embedded systems, robotics, and electronics projects. In this article, we will explore the 8051 microcontroller and its various aspects, as covered in the book by Subrata Ghoshal.

Introduction to the 8051 Microcontroller

The 8051 microcontroller is an 8-bit microcontroller that is based on the Harvard architecture. It has a wide range of applications, including industrial control systems, medical devices, automotive systems, and consumer electronics. The microcontroller has a simple and efficient architecture, making it easy to program and use.

Key Features of the 8051 Microcontroller

The 8051 microcontroller has several key features that make it a popular choice among designers and engineers. Some of its key features include:

Book Overview: 8051 Microcontroller by Subrata Ghoshal

The book "8051 Microcontroller" by Subrata Ghoshal is a comprehensive guide to the 8051 microcontroller. The book covers all aspects of the microcontroller, including its architecture, programming, and applications. The book is written in a clear and concise manner, making it easy for readers to understand the concepts.

The book covers the following topics:

Downloading the PDF

If you are interested in downloading the PDF version of the book "8051 Microcontroller" by Subrata Ghoshal, you can search for it online. However, please note that downloading copyrighted materials without permission is illegal. You can also purchase the book from online retailers or check it out from a library.

Conclusion

The 8051 microcontroller is a powerful and versatile microcontroller that has a wide range of applications. The book "8051 Microcontroller" by Subrata Ghoshal is a comprehensive guide to the microcontroller, covering its architecture, programming, and applications. Whether you are a student, hobbyist, or professional engineer, this book is a valuable resource for anyone interested in working with the 8051 microcontroller.

Introduction

The 8051 microcontroller is one of the most popular and widely used microcontrollers in the world. It was first introduced by Intel in 1980 and has since become a standard component in many embedded systems. The 8051 microcontroller is an 8-bit microcontroller that is based on the MCS-51 architecture. It is a powerful and versatile microcontroller that is widely used in a variety of applications, including industrial control systems, medical devices, and consumer electronics.

Architecture of 8051 Microcontroller

The 8051 microcontroller has a Harvard architecture, which means that it has separate buses for program memory and data memory. This allows for concurrent access to both program and data memory, making it a very efficient microcontroller. The 8051 microcontroller has a total of 128 bytes of on-chip RAM, which is used for storing data. It also has a program memory of 4KB, which is used for storing the program.

The 8051 microcontroller has a total of 32 I/O pins, which can be used for input/output operations. It also has a number of peripherals, including two 16-bit timers/counters, a full-duplex UART, and a serial interface.

Features of 8051 Microcontroller

The 8051 microcontroller has a number of features that make it a popular choice for embedded system design. Some of its key features include:

Applications of 8051 Microcontroller

The 8051 microcontroller is widely used in a variety of applications, including:

Programming of 8051 Microcontroller

The 8051 microcontroller can be programmed using a variety of programming languages, including assembly language and C. The most common programming language used for the 8051 microcontroller is assembly language.

Conclusion

In conclusion, the 8051 microcontroller is a powerful and versatile microcontroller that is widely used in a variety of applications. Its high-performance architecture, low-power consumption, and on-chip memory make it a popular choice for embedded system design. The 8051 microcontroller is widely used in industrial control systems, medical devices, and consumer electronics. With its ease of use and programming, the 8051 microcontroller is a great choice for students and professionals alike.

References

You can download the PDF version of the book "8051 Microcontroller" by Subrata Ghoshal from various online sources, such as:

Please note that downloading copyrighted materials without permission is illegal. You can purchase the book from online retailers or check it out from a library.

Introduction

The 8051 microcontroller is a popular 8-bit microcontroller developed by Intel in 1980. It is widely used in embedded systems, robotics, and electronics projects. The 8051 microcontroller is known for its simplicity, ease of use, and versatility. In this guide, we will explore the architecture, programming, and applications of the 8051 microcontroller.

Architecture of 8051 Microcontroller

The 8051 microcontroller has the following architecture:

Programming 8051 Microcontroller

The 8051 microcontroller can be programmed using assembly language or C language. Here are the basic steps to program the 8051 microcontroller:

  1. Choose a programming language: You can choose either assembly language or C language to program the 8051 microcontroller.
  2. Write the program: Write your program using the chosen language.
  3. Assemble or compile the program: Assemble or compile the program to generate machine code.
  4. Download the program: Download the machine code into the 8051 microcontroller.

8051 Microcontroller Programming using Assembly Language

Here are some basic assembly language instructions used to program the 8051 microcontroller:

Example assembly language program:

ORG 0000H
MOV R0, #05H
LOOP:
 MOV A, R0
 ADD A, #01H
 MOV R0, A
 DJNZ R0, LOOP
END

8051 Microcontroller Programming using C Language

Here are some basic C language functions used to program the 8051 microcontroller:

Example C language program:

#include <8051.h>
void main() 
 unsigned char i;
 for (i = 0; i < 5; i++) 
 // do something

Applications of 8051 Microcontroller

The 8051 microcontroller is widely used in various applications, including:

Interfacing 8051 Microcontroller with External Devices

The 8051 microcontroller can be interfaced with external devices such as:

Downloading 8051 Microcontroller PDF

You can download the 8051 microcontroller PDF by Subrata Ghoshal from various online sources. Here are a few steps to follow:

  1. Search online: Search online for "8051 microcontroller subrata ghoshal pdf download".
  2. Visit a relevant website: Visit a relevant website that provides the PDF download link.
  3. Click on the download link: Click on the download link to download the PDF.

Conclusion

The 8051 microcontroller is a popular and versatile microcontroller that is widely used in embedded systems, robotics, and electronics projects. This guide provides a comprehensive overview of the 8051 microcontroller architecture, programming, and applications. You can download the 8051 microcontroller PDF by Subrata Ghoshal from various online sources.

The cursor blinked rhythmically, a steady heartbeat on a screen of black. Outside the window of the third-floor lab, the city of Kolkata was drowning in a torrential monsoon downpour, but inside, Arjun was dry, frustrated, and running out of time.

His final year engineering project—a traffic light control system with adaptive timing—was due in forty-eight hours. The hardware was soldered, the power supply was humming, but the soul of the machine, the assembly code, was a mess of syntax errors and logic loops.

Arjun pushed his chair back and rubbed his eyes. He knew the theory. He knew about the Accumulator, the PSW register, and the mysterious Timer 1 Mode 2. But putting it all together into something that didn't just flash an LED but actually thought? That required a guide. And he didn't have one.

His professor, a kindly but busy man, had simply said, "Refer to Ghoshal. He explains the architecture best."

Arjun had spent the last three hours in a digital wild goose chase. The search query was simple, yet elusive: "8051 Microcontroller Subrata Ghoshal PDF download."

The internet, usually an ocean of information, seemed to have dried up regarding this specific title. He found broken links from defunct student forums, shady websites promising the file but delivering malware, and incomplete snippets on Scribd that required a credit card he didn't have.

"Just a PDF," Arjun whispered to the humming CPU. "I just need to see the chapter on Interrupt Priority."

He refreshed the search page. The third link looked different. It wasn't a flashy download button. It was a plain, text-based thread on an archived university bulletin board from 2009.

User 'RetroTech' says: Looking for Ghoshal's book. The chapter on Boolean Processors is missing from my copy. Can anyone help? Reply from 'Guest_88': Check the library server at the old hostel. They digitized the electrical section in '08. The file name is SG_8051_v2.pdf.

Arjun frowned. A library server? He clicked the link provided by 'Guest_88'. It timed out. He sighed, ready to close the laptop. But then, he remembered a trick his senior had taught him for accessing archived educational nodes. He typed the IP address directly into his browser, bypassing the domain name.

The screen flickered. A stark, white page loaded.

INDEX OF /EBOOKS/ARCHIVED/MICROCONTROLLERS/

It was a directory listing, a digital graveyard of forgotten textbooks. He scrolled down. ...Mazidi.pdf ...Ayala.pdf ...Kenneth.pdf 8-bit CPU with a clock speed of up

And there it was. Ghoshal_8051_Architecture.pdf

Arjun held his breath. He right-clicked. Save link as.

The download dialog box appeared. He hesitated. The file size was 18.4 MB. It felt… dense. Heavy with knowledge. He clicked Save.

The progress bar crept forward. 10%... 25%...

Suddenly, the power flickered. The lab lights dimmed, buzzing threateningly. The storm outside intensified, thunder cracking directly overhead. The monitor’s glow wavered. Arjun watched the download bar, his heart hammering against his ribs. If the UPS failed now, the partial file would corrupt, and he’d be back to square one.

50%... 75%...

"Don't you dare," he gritted his teeth.

The file hit 98%. The lights went out completely, plunging the lab into darkness. The hum of the computers died. The only light came from Arjun’s laptop battery, a small island of white light in the black room.

Download Complete.

Arjun exhaled, a long, shaky breath. He minimized the browser and opened the file. It loaded, crisp and sharp.

There, on the screen, was the contents page. Chapter 7: Interrupts and Timer Programming by Subrata Ghoshal. He scrolled through the scanned pages. They were old, perhaps scanned from a physical copy with margin notes written in pencil by a student long graduated. The diagrams of the SFR (Special Function Registers) were hand-drawn in the book and meticulously scanned.

He found the section on the Timer 1 interrupt. The explanation was elegant. Ghoshal didn't just give code; he explained the why. He explained how the microcontroller felt the interrupt, how it paused, saved its context, and jumped to the subroutine.

For the next six hours, Arjun didn't move. The storm raged, the lab remained dark, but he was illuminated by the glow of the PDF. He wasn't just reading; he was having a conversation with the author across time and space. Subrata Ghoshal’s words, digitized years ago, were rewriting the logic in Arjun’s mind.

When the sun finally rose, painting the wet streets in hues of orange, Arjun typed the final command into his assembly file.

ACALL TRAFFIC_LOGIC

He compiled it. 0 Errors. 0 Warnings.

He connected his laptop to the hardware board. He pressed the reset button. The traffic lights—Red, Amber, Green—lit up in a sequence he had written, precise and intelligent.

It worked. It wasn't just code anymore; it was a system.

Arjun leaned back, exhausted but triumphant. He looked at the PDF icon on his desktop. It sat there, innocuous and grey. But to him, it was a key. He renamed the file, organizing it into his project folder, and then, almost reverently, he closed the tab.

He packed his bag, stepping over the sleeping bodies of other students who had camped out in the lab. As he walked out into the fresh morning air, he realized that the "download" he had spent hours hunting for was worth far more than the frustration it cost. It was the bridge between a student and an engineer.

The Ultimate Guide to 8051 Microcontroller by Subrata Ghoshal: A Comprehensive Resource for Embedded System Enthusiasts

The 8051 microcontroller is one of the most popular and widely used microcontrollers in the world of embedded systems. Its simplicity, ease of use, and versatility have made it a favorite among engineers, students, and hobbyists alike. For those looking to gain in-depth knowledge of this microcontroller, the book "8051 Microcontroller" by Subrata Ghoshal is an invaluable resource. In this article, we will explore the book's contents, its significance, and provide a guide on how to download the PDF version.

Introduction to the 8051 Microcontroller

The 8051 microcontroller is an 8-bit microcontroller developed by Intel in the 1980s. It has a wide range of applications in various fields, including robotics, automation, communication systems, and more. The microcontroller's architecture, instruction set, and peripherals make it an ideal choice for many embedded system projects.

About the Author: Subrata Ghoshal

Subrata Ghoshal is a renowned author and expert in the field of embedded systems and microcontrollers. With years of experience in teaching and research, he has written several books on microcontrollers, including the popular "8051 Microcontroller" book. His writing style is clear, concise, and easy to understand, making complex concepts accessible to readers of all levels.

Book Overview: "8051 Microcontroller" by Subrata Ghoshal

The book "8051 Microcontroller" by Subrata Ghoshal is a comprehensive guide to the 8051 microcontroller, covering its architecture, programming, and applications. The book is divided into several chapters, each focusing on a specific aspect of the microcontroller.

Key Features of the Book:

  1. In-depth coverage of 8051 microcontroller architecture: The book provides a detailed explanation of the microcontroller's architecture, including its memory organization, instruction set, and peripherals.
  2. Programming examples and projects: The book includes numerous programming examples and projects to illustrate the concepts and help readers gain practical experience.
  3. C and assembly language programming: The book covers both C and assembly language programming, allowing readers to choose the best approach for their projects.
  4. Interfacing with external devices: The book explains how to interface the 8051 microcontroller with external devices, such as LEDs, LCDs, and sensors.
  5. Applications and case studies: The book presents several real-world applications and case studies to demonstrate the microcontroller's capabilities.

Why is this Book Important?

The "8051 Microcontroller" book by Subrata Ghoshal is an essential resource for anyone interested in learning about embedded systems and microcontrollers. Here are some reasons why:

  1. Comprehensive coverage: The book provides a thorough understanding of the 8051 microcontroller, making it an ideal textbook for students and a valuable reference for professionals.
  2. Practical approach: The book's focus on practical examples and projects helps readers gain hands-on experience with the microcontroller.
  3. Easy to understand: The author's writing style is clear and concise, making complex concepts accessible to readers of all levels.

Downloading the PDF Version

For those interested in downloading the PDF version of "8051 Microcontroller" by Subrata Ghoshal, here are some steps to follow:

  1. Search online repositories: You can search online repositories, such as Academia.edu, ResearchGate, or online libraries, for the book's PDF version.
  2. Check online marketplaces: You can also check online marketplaces, such as Amazon or Google Books, for a digital version of the book.
  3. Visit the author's website: Sometimes, authors provide a link to download their books or resources from their personal website.

Conclusion

The "8051 Microcontroller" book by Subrata Ghoshal is a valuable resource for anyone interested in learning about embedded systems and microcontrollers. Its comprehensive coverage, practical approach, and easy-to-understand writing style make it an ideal textbook for students and a valuable reference for professionals. By downloading the PDF version, readers can access the book's contents and gain a deeper understanding of the 8051 microcontroller.

Keyword density:

Word count: approximately 700 words

Note that this article is a general guide and not an actual download link for the PDF version of the book. Readers are advised to follow the steps mentioned above to download the book from authorized sources.

Where to Get the PDF Legally (Or Alternative Access)

  1. Google Books / Amazon Kindle – Pearson has released an ebook edition. You can borrow it with Kindle Unlimited (free trial for 30 days).
  2. University E-libraries – If you are a student at IIT, NIT, or any AICTE-approved college, check your NDL (National Digital Library) membership. They have licensed PDFs for free.
  3. Archive.org – Sometimes, older editions (2008) appear under controlled digital lending.
  4. Pearson’s Official Website – They occasionally offer sample chapters (usually Chapters 1 and 5) as free PDFs for course adoption.

Sample Program from the Book (Often Copied into PDF Notes)

To prove the book’s practical value, here is a classic Ghoshal-style example: Interfacing a 4x4 keypad to display the pressed key on a 7-segment display.

(Assembly snippet – typical of Ghoshal’s teaching style)

ORG 0000H
MAIN: MOV P1, #0FH    ; Configure lower bits as input
       CALL SCAN
       SJMP MAIN

SCAN:  MOV P1, #0EFH   ; Row 0 low
JB P1.0, NEXT1
MOV A, #1       ; Key '1'
CALL DISPLAY
...

The book doesn’t just give code. It explains why you need pull-up resistors on Port 1 and how to debounce mechanical switches. Row 0 low JB P1.0

Alternatives if You Cannot Find the PDF

If the Subrata Ghoshal PDF is unavailable, consider these excellent (and often legally free) resources:

| Resource | Focus Area | Availability | | :--- | :--- | :--- | | The 8051 Microcontroller by Kenneth Ayala | Deep hardware insights | Used copies cheap | | Mazidi & Mazidi | Extensive C programming | Free PPTs online | | Keil uVision Software Manual | Practical simulation | Free PDF from Keil | | Atmel (now Microchip) Datasheets | Original register maps | Always free |