Peripheral Component Interconnect

The Peripheral Component Interconnect, or PCI Standard (in practice almost always shortened to PCI), specifies a computer bus for attaching peripheral devices to a computer motherboard.The PCI Bus is a high performance bus for interconnecting chips, expansion boards, and processor/memory subsystems.

• Wiki article on PCI

Non-Return-to-Zero Inverted

NRZI encoding is used for data transmission in the standard USB.
http://en.wikipedia.org/wiki/NRZI

EIA standards :RS232/422/485

RS 232,422,485 -quick reference

RS 232 tutorial - A very informative webpage - Recommended

Selecting and Using RS-232, RS-422, and RS-485 Serial Data Standards
An application note from Maxim semiconductors.Includes connection firures for RS232.422,485 and specifications

Dallas Semiconductor application note on RS232 - simple

RS422/485 application note

Comparing Bus Solutions

Texas Instruments Application Report "Comparing Bus Solutions" February 2004, Texas Instruments,

USB On-The-Go

Every USB communications is between a host and a device. Devices can't communicate with each other directly. The On-The-Go supplement to the USB specification defines a new type of device that can function as both a device and as a scaled-back host (but not both at the same time). When functioning as a device, the On-The-Go device can communicate with a PC or other USB host. When functioning as a host, the device can connect to USB peripherals.

• USB On-The-Go: a Tutorial
• Introduction to USB On-The-Go

Universal Serial Bus

• Home of USB Implementers Forum, Inc.
• USB 2.0 specification
• USB Central
• Wiki article on USB
• Short, simple description of USB with good pictures of cable breakdown and plugs
• USB in a nut shell
  

Switch debouncing

Switches can do some really odd things. Most engineers learn this dirty little secret soon after connecting a switch or a relay to a digital system. Switches don't make and break cleanly on the time scales of digital systems. Instead, a typical switch makes multiple transitions during the tens of milliseconds required to open or close, due to effects that include age, operating inertia, mechanical design, and the microscopic condition of the switch-contact surfaces. Commonly called "switch bounce," this behavior is an inescapable fact of life.

- application note 287 :Switch Bounce and Other Dirty Little Secrets,Maxim semiconductors

some resources--

• a guide to debouncing
• application note 287,Maxim semiconductors
• http://www.bioinspired.com/users/ajg112/electronics/debounce.shtml
• html format of the guide to debouncing
• MAX6816, MAX6817, MAX6818 ±15kV ESD-Protected, Single/Dual/Octal, CMOS Switch Debouncers - Maxim/Dallas Semiconductor.
• MAX 6816,Max 6817,MAX6818 datasheet

Serial v/s Parallel transmission - which is better?

Serial v/s Parallel transmission - which is better?

see this wiki article .....

http://en.wikibooks.org/wiki/Communication_Systems/Parallel_vs_Serial

a round up of microcontroller interfacing techniques

Micro-controllers are useful to the extent that they communicate with other devices, such as sensors, motors, switches, keypads, displays, memory and even other micro-controllers.Many interface methods have been developed over the years to solve the complex problem of balancing circuit design criteria such as features, cost, size, weight, power consumption,reliability, availability, manufacturability.

The following document is a summary of some of these interfacing techniques
http://www.bipom.com/applications/micro_interfacing.pdf

Sorting algorithm animation

Sorting algorithms:

We all know that Quicksort is one of the fastest algorithms for sorting. It's not often, however, that we get a chance to see exactly how fast Quicksort really is. The following link will lead you to applets chart the progress of several common sorting algorithms namely Bubblesort , Insertionsort , Quicksort and Select sort

sorting algorithm animation

wiki wiki ??

Wiki Wiki is a reduplication of wiki, a Hawaiian-language word for fast. The word "wiki" (/wiːkiː wiːkiː/) is a shorter form of wiki wiki. WikiWikiWeb was the first site to be called a wiki., Ward Cunningham started developing WikiWikiWeb in 1994, and installed it on Internet domain c2.com on March 25, 1995. It was named by Cunningham, who remembered a Honolulu International Airport counter employee telling him to take the so-called "Wiki Wiki" Chance RT-52 shuttle bus line that runs between the airport's terminals. According to Cunningham, "I chose wiki-wiki as an alliterative substitute for 'quick' and thereby avoided naming this stuff quick-web."

http://en.wikipedia.org/wiki/Wiki

I2C Bus

Almost 20 years ago the I2C bus was designed by Philips to allow easy communication between c omponents which reside on the same circuit board. Philips Semiconductors migrated to NXP in 2006.

The name I2C translates into "Inter IC". The original communication speed was defined with a maximum of 100 kbit per second and many applications don't require faster transmissions. For those that do there is a 400 kbit and - since 1998 - a high speed 3.4 Mbit option available.

Meanwhile I2C is not only used on single boards, but also to connect components which are linked via cable. Simplicity and flexibility are key characteristics that make this bus especially attractive for consumer and automotive electronics.

to know more about I2C Bus---

http://i2c-bus.org/

http://www.esacademy.com/faq/i2c/

The I2C-Bus and how to use it is a well-known document from Philips discussing the use of this bus in applications.

Wiki article on I2C bus

Reed Relays

As a relay is a switch controlled by an electromagnet, so a reed relay is one or more reed switches controlled by an electromagnet. The contacts are of magnetic material; thus the electromagnet acts directly on them rather than requiring an armature to move them. Sealed in a long, narrow glass tube, the contacts are protected from corrosion, thus are ordinarily plated with silver rather than precious metals. The most common reed relays of the late 1930s through the 80s had two reed switches inserted into holes in the bobbin. Since the moving parts are small, reed relays are capable of faster switching than most others.

Reed Switches (wiki)
Reed Relay Applications

some interesting motor applications

A document discussing some interesting applications of various types of motors

http://www.compumotor.com/catalog/cataloga/A72-A96.pdf

stepper motor basics

A stepper motor is a brushless, synchronous electric motor that can divide a full rotation into a large number of steps, for example, 200 steps. When commutated electronically, the motor's position can be controlled precisely, without any feedback mechanism (see open loop control)

Some web resources on Stepper Motors:

Stepper motor Basics
Control of Stepping Motors - A Tutorial
A Wiki article on Stepper motors
Nice Animation of a stepping Motor : A German webpage.Please use the slider labelled as continuous to vary speed and run the animation.The stepping modes can also be changed.The type of winding can be selected from the top left corner of the animation

the microsoft way.............

"Microsoft programs are generally bug-free. If you visit the Microsoft hotline, you'll literally have to wait weeks if not months until someone calls in with a bug in one of our programs. 99.99% of calls turn out to be user mistakes. I know not a single less irrelevant reason for an update than bugfixes. The reasons for updates are to present more new features."

-- Bill Gates on code stability, from Focus Magazine

DAC 0808 datasheet

http://www.national.com/mpf/DA/DAC0808.html

ADC 0804 datasheet

http://www.national.com/mpf/DC/ADC0804.html

Understanding DC Electrical Characteristics of Microcontrollers

For the inexperienced designer, understanding the electrical characteristics presented in an integrated circuit data sheet can be confusing. If misinterpreted, a new design could prove disastrous. This tutorial is intended to demystify the steady state characteristics of the Maxim microcontroller product family.(but surely relevant for any microcontroller data sheet)
http://www.maxim-ic.com/appnotes.cfm/an_pk/1087

is 8051 a RISC or a CISC processor?

8051 is a CISC () processor

"CISC (complex Instruction Set Computer), with all the possible adressing modes on the instructions"

although the actual number of instructions is quite small!

So, taking the words at face-value, it is quite "simple" relative to something "complex" like a Pentium;
It is also quite "simple" relative to something like the ARM - which is RISC!

"CISC" and "RISC" have to do with design philosophy rather than raw counts of numbers of instructions...

see the following discussion forum for more
http://www.keil.com/forum/docs/thread11113.asp

C v/s Assembly

What are the merits and demerits of using C over assembly language for microcontroller programming,just see this discussion
http://www.keil.com/forum/docs/thread11112.asp#msg53554

RISC v/s CISC

Source:
http://lobe.ibme.utoronto.ca/presentations/Microcontroller/index.htm

8051 ports

The following thread sheds light on:

• the status of 8051 port pins at power on/reset
• what happens when a 1 is written to a port latch

http://www.keil.com/forum/docs/thread11092.asp#msg53474

http://www.8052.com/faqs.phtml?FAQ=120176

Keil C compiler online manual

http://www.keil.com/support/man/docs/c51

von Neumann architecture and Harvard architecture

The von Neumann architecture is a computer design model that uses a processing unit and a single separate storage structure to hold both instructions and data. It is named after mathematician and early computer scientist John von Neumann. Such a computer implements a universal Turing machine, and the common "referential model" of specifying sequential architectures, in contrast with parallel architectures. The term "stored-program computer" is generally used to mean a computer of this design, although as modern computers are usually of this type, the term has fallen into disuse.

http://en.wikipedia.org/wiki/Von_Neumann_architecture

Harvard architecture is a computer architecture with physically separate storage and signal pathways for instructions and data. The term originated from the Harvard Mark I relay-based computer, which stored instructions on punched tape (24 bits wide) and data in electro-mechanical counters (23 digits wide). These early machines had limited data storage, entirely contained within the data processing unit, and provided no access to the instruction storage as data, making loading and modifying programs an entirely offline process.

http://en.wikipedia.org/wiki/Harvard_architecture

The following link also provides some insight into the topic especially wrt ARM cores
http://www.arm.com/support/faqip/3738.html

Build Your Own ARM Cross Compiler Toolchain

GNUARM is a set of open source GNU compiler for ARM microcontroller. The toolchain consists of the GNU binutils, GCC compiler set, Newlib and Insight, the graphical user interface to GNU debugger for Windows and Linux. This article will guide the building process of GNUARM toolchain only for Linux users. For Windows users, there have the installer executable EXE files already. www.scienceprog.com has a tutorial on setting up this tool on Windows environment.

(more…)

8051 mcu, von Neumann vs Harvard Architectures

We can classify computer architectures into two categories:

von Neumann architecture: computers has a single, common memory space in which both program instructions and data are stored. There is a single internal data bus that fetches both instructions and data. They can not be performed at
the same time

Harvard architecture: computers have separate memory areas for program instructions and data. There are two or more internal data buses, which allow simultaneous access to both instructions and data. The CPU fetches program instructions on the program memory bus.

(more…)

iF-DEV Free Tools for ARM7/9/XScale

You can get started developing on an ARM for only $99 with dev. kit from iSystem AG. iF-DEV is a complete development tool solution for ARM7, ARM9 and XScale (see Fig. below). The system includes includes everything you need to get started. The small target board contains an ARM-based NXP LPC2138 microcontroller along with a USB-based JTAG debugger. Power to the target is provided by the JTAG’s USB interface.

(more…)

Microcontroller Programmer DIY

I search about this issue for a while, "Building programmer of our own designs". I found a few of open source programmer projects so that every body can use and contribute it. Here is an opportunity of learning the microcontroller programmer designs from that open schematics. (more…)

Learn Embedded Linux with ARMulator

uClinux is an excellent way to study the embedded operating systems for enginner, student, hobbiest, Linux-enthusiast. I am interested in Embedded Linux for ARM microcontroller. Before buying a new mcu evaluation board, there is a smart way to study the Embedded Linux. That is studying it with the emulator called ARMUlator. (more...)

Microcontrollers and the GNU Public License (GPL)

Open Source software is released according to the terms of the GNU Public License, GPL. The GPL is intended to guarantee your rights to use, modify and copy the subject software. Along with the rights comes an obligation. If you modify and subsequently distribute software covered by the GPL, you are obligated to make available the modified source code. The changes become a "derivative work" which is also subject to the terms of the GPL. This allows other users to understand the software better and to make further changes if they wish. (more...)

Linux for Embedded Systems

For a microcontroller learner, Embedded System is a challenge. Linux are used as an operating system for the modern embedded devices. I am a one who are trying to study Linux on an embedded microcontroller, i.e., 8051 mcu and ARM. Let's start together! (more...)

Understanding Processor Architecture: RISC versus CISC

Popular processor designs can be broadly divided into two categories: Complex Instruction Set Computers (CISC) and Reduced Instruction Set Computers (RISC). The dominant processor in the PC market, Pentium, belongs to the CISC category. However, the recent trend is to use the RISC designs. Even Intel has moved from CISC to RISC design for their 64-bit processor. (more...)

ASEM-51 step-by-step Installation on Windows XP

Last time I wrote an installation for ASEM-51, a two-pass macro assembler for the Intel MCS-51 family of microcontrollers, using the batch file INSTALL.BAT. For someone who do not like anything that is running automatically, or things are not quite clear, here is an step-by-step installation guide for ASEM-51. (more...)

Learning Machine Code with 8-bit Microcontrollers

To understand deeply in processor architecture, we have to learn the Machine Code. I decide to select the 8051 microcontroller as a microprocessor model. A microcontroller (or MCU) is a computer-on-a-chip. They integrate many modules on one chip such as RAM, Flash memory, EEPROM, serial ports (UARTs), I²C, Serial Peripheral Interface (SPI), analog-to-digital converters (ADC), clock generator (XTAL) and more. (more...)

A Guide to ARM Microcontroller

This guide suit a beginner who are going to learn ARM Microcontroller>>>.

Updated!

Understanding Processor Architecture: Machine and Assembly Language >>>

Understanding Processor Architecture: Simplify Computer Complexity

I have updated an article for the series on "Understanding Processor Architecture":

Understanding Processor Architecture: Simplify Computer Complexity >>>

Understanding Processor Architecture: ISA

I am writing a series on "Understanding Processor Architecture". And, here is the first article:

Understanding Processor Architecture: ISA >>>

AVR flash MCUs roll for high-volume USB apps

Expanding its family of AVR MCUs, Atmel has launched two new devices for high-volume USB applications ranging from HID to wireless adaptors.... More>>>

Atmel 8051 MCUs roll for high-volume USB apps

Atmel unrolled 8051-based USB MCUs that feature a USB Full-Speed controller, UART, SPI and a two-wire interface allowing an easy connection to companion devices.... Source: http://www.eetasia.com/ART_8800456879_1034362_c187178820070316.HTM?from=RSS

Configurable ARM-powered SoCs target Linux devices

STMicroelectronics (ST) is sampling a pair of configurable SoCs (system-on-chip processors) powered by ARM9 cores and 600K-gate configurable logic blocks. The SPEAr (structured processor enhanced architecture) Head600 and dual-core SPEAr Plus600 run Linux, support DDR/DDR2 external memory, and target printer, fax, and POS (point-of-sales) devices.... More>>>

Malaysia develops 'smallest' RFID chip

After two years of R&D, the Malaysia Microchip Project gains success with the release of the world's 'smallest' RFID microchip.... More

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NEC expands MCU line for inverter control apps

NEC Electronics has added six highly integrated devices to its 32bit RISC MCU product portfolio for inverter-control systems.... Source: http://www.eetasia.com/ART_8800451964_1034362_d2fdd5b620070206.HTM?from=RSS 

Evaluation for 32bit ARM7-based MCUs

Low-cost evaluation board is based on the STR750FV2T6 processor - the latest series of super-integrated single-chip 32bit ARM7-based MCUs from STMicroelectronics.... Source: http://rss1.mediafed.com/feed/protalk/electronics/?link=0c4f1274eda21e674c5e04d05613d530 

18-bit ADC in SOT-23 package

Microchip claims its MCP3421 ADC is the highest resolution ADC available in a 6-pin SOT-23 package. The low-power, 18-bit, delta-sigma device features an integrated voltage reference, oscillator and programmable gain amplifier. This reduces the need for external components and enables a smaller overall design. The ADC uses an I²C compatible serial interface, operates from a single power supply (2,7 to 5,5 V), and consumes just 155 μA during continuous conversion at 5 V. The onboard PGA allows users to select gains of x1, x2, x4 or x8 before the A-to-D conversion takes place, allowing very high-resolution conversion of even small input signals.... Source: http://dataweek.co.za/news.aspx?pklNewsId=23425