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AVR Tutorial - Input / Output

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Overview You cannot imagine to use microcontroller without using any of its i/o pins. Finally its all about : taking input , processing it and generating output ! Thus i/o registers and their correct settings is indispensable part while learning to program any uC. We will learn how to use AVR ports and actually ‘code’ for writing/reading data to/from port pins. It is slightly confusing for beginners, however once you understand it, you will certainly appreciate the way it is designed. NOTE : I will frequently refer to ‘configuring pin’ or simply ‘pin’. Remember, a port has multiple pins. Thus in order to change setting for one port, you have to change setting for all port pins of that port. To change setting for one single pin of the port, you have to change a particular bit in associated register. Got that ? If not read this para again. Registers AVR is 8 bit microcontroller. All its ports are 8 bit wide. Every port has 3 registers associated with it each one with 8 bits...
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AVR ADC Analog to Digital Converter

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What is an ADC? An ADC, or Analog to Digital Converter, allows one to convert an analog voltage to a digital value that can be used by a microcontroller. There are many sources of analog signals that one might like to measure. There are analog sensors available that measure temperature, light intensity, distance, position, and force, just to name a few. Introduction The AVR ADC The AVR ADC allows the AVR microcontroller to convert analog voltages to digital values with few to no external parts. The author wrote this tutorial with the ATMega128 in mind, though other AVRs use similar hardware. The ADC built into the ATMega128 is capable of 10 bit resolution. The ATMega128 microcontroller has 8 ADC channels, allowing up to 8 analog sources to be attached to the microcontroller. The 8 ADC channels are connected to the internal DAC through a device called a multiplexer. The multiplexer connects the 8 ADC channels (the 8 pins of Port F on the ATMega128) to the internal ADC. One channel...
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Introduction to REST

Building Web Services the REST Way Roger L. Costello I will first provide a brief introduction to REST and then describe how to build Web services in the REST style. What is REST? REST is a term coined by Roy Fielding in his Ph.D. dissertation [1] to describe an architecture style of networked systems. REST is an acronym standing for Representational State Transfer. Why is it called Representational State Transfer? The Web is comprised of resources. A resource is any item of interest. For example, the Boeing Aircraft Corp may define a 747 resource. Clients may access that resource with this URL: http://www.boeing.com/aircraft/747 A representation of the resource is returned (e.g., Boeing747.html). The representation places the client application in a state . The result of the client traversing a hyperlink in Boeing747.html is another resource is accessed....
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