AVR is a family of microcontrollers developed by Atmel beginning in These are modified Harvard architecture 8-bit RISC single-chip microcontrollers. AVR was one of the first microcontroller families to use on-chip flash memory for program storage, as opposed to one-time programmable ROMEPROMor EEPROM used by other microcontrollers at the time. AVR microcontrollers find many applications as embedded systems ; they are also used in the Arduino line of open source board designs. The AVR architecture was conceived by two students at the Norwegian Institute of Technology NTH[1] Alf-Egil Bogen [2] and Vegard Wollan.

The original AVR MCU was developed at a local ASIC house in Trondheim, Norwaycalled Nordic VLSI at the time, now Nordic Semiconductorwhere Bogen and Wollan were working as students.

The designers worked closely with compiler writers at IAR Systems to ensure that the AVR instruction set provided efficient compilation of high-level languages. Atmel says that the name AVR is not an acronym and does not stand for anything in particular. The creators of the AVR give no definitive answer as to what the term "AVR" stands for.

Among the first of the AVR line was the AT90S, which in a pin DIP package has the same pinout as an microcontroller, including the external multiplexed address and data bus. The polarity of the RESET line was opposite 's having an active-high RESET, while the AVR has an active-low RESETbut other than that the pinout was identical.

The AVR 8-bit microcontroller architecture was introduced in ByAtmel had shipped million AVR flash microcontrollers. The AVR is a modified Harvard architecture machine, where program and data are stored in separate physical memory systems that appear in different address spaces, but having the ability to read data items from program memory using special instructions.

FlashEEPROMand SRAM are all integrated onto a single chip, removing the need for external memory in most applications. Some devices have a parallel external bus option to allow adding additional data memory or memory-mapped devices. Almost all devices except the smallest TinyAVR chips have serial interfaces, which can be used to connect larger serial EEPROMs or flash chips. Program instructions are stored in non-volatile flash memory. Although the MCUs are 8-bit, each instruction takes one or two bit words.

The size of the program memory is usually indicated in the naming of the device itself e. There is no provision for off-chip program memory; all code executed by the AVR core must reside in the on-chip flash. Some small models also map the program ROM into the data address space, but larger models do not.

The AVRs have 32 single-byte registers and are classified as 8-bit RISC devices. The very smallest of the tinyAVR variants use a reduced architecture with only 16 registers r0 through r15 are omitted which are not addressable as memory locations. In addition, these devices have slight deviations from the standard AVR instruction set.

Conversely, the indirect load instruction's LD bit address space is expanded to also include non-volatile memory such as Flash and configuration bits; therefore, the LPM instruction is unnecessary and omitted. In the XMEGA variant, the working register file is not mapped into the data address space; as such, it is not possible to treat any of the XMEGA's working registers as though they were SRAM. The actual SRAM is located after these ranges, starting at Each GPIO port on a tiny or mega AVR drives up to eight pins and is controlled by three 8-bit registers: DDR xPORT x and PIN xwhere x is the port identifier.

Almost all AVR microcontrollers have internal EEPROM for semi-permanent data storage. Like flash memory, EEPROM can maintain its contents when electrical power is removed. In most variants of the AVR architecture, this internal EEPROM memory is not mapped into the MCU's addressable memory space. However, some devices in the SecureAVR AT90SC family [9] use a special EEPROM mapping to the data or program memory, depending on the configuration.

The XMEGA family also allows the EEPROM to be mapped into the data address space. Note that erase and write can be performed separately in many cases, byte-by-byte, which may also help prolong life when bits only need to be set to all 1s erase or selectively cleared to 0s write. Atmel's AVRs have a two-stage, single-level pipeline design. This means the next machine instruction is fetched as the current one is executing.

Most instructions take just one or two clock cycles, making AVRs relatively fast among eight-bit microcontrollers. The AVR processors were designed with the efficient execution of compiled C code in mind and have several built-in pointers for the task. The AVR instruction set is more orthogonal than those of most eight-bit microcontrollers, in particular the clones and PIC microcontrollers with which AVR competes today. However, it is not completely regular:.

Additionally, some chip-specific differences affect code generation. The mostly regular instruction set makes programming it using C or even Ada compilers fairly straightforward. GCC has included AVR support for quite some time, and that support is widely used. In fact, Atmel solicited input from major developers of compilers for small microcontrollers, to determine the instruction set features that were most useful in a compiler for high-level languages.

Lower-powered operation usually requires a reduced clock speed. All recent Tiny, Mega, and Xmega, but not 90S AVRs feature an on-chip oscillator, removing the need for external clocks or resonator circuitry.

Some AVRs also have a system clock prescaler that can divide down the system clock by up to This prescaler can be reconfigured by software during run-time, allowing the clock speed to be optimized. Branches in the latest "3-byte PC" parts such as ATmega are one cycle slower than on previous devices. AVRs have a large following due to the free and inexpensive development tools available, including reasonably priced development boards and free development software.

The AVRs are sold under various names that share the same basic core, but with different peripheral and memory combinations. There are many means to load program code into an AVR chip. The methods to program AVR chips varies from AVR family to family. Most of the methods described below use the RESET line to enter programming mode.

In order to avoid the chip accidentally entering such mode, it is advised to connect a pull-up resistor between the RESET pin and the positive power supply. The in-system programming ISP programming method is functionally performed through SPIplus some twiddling of the Reset line. As long as the SPI pins of the AVR are not connected to anything disruptive, the AVR chip can stay soldered on a PCB while reprogramming. All that is needed is a 6-pin connector and programming adapter. This is the most common way to develop with an AVR.

The Atmel AVRISP mkII device connects to a computer's USB port and performs in-system programming using Atmel's software. The Program and Debug Interface PDI is an Atmel proprietary interface for external programming and on-chip debugging of XMEGA devices. The PDI supports high-speed programming of all non-volatile memory NVM spaces; flash, EEPROM, fuses, lock-bits and the User Signature Row. This is done by accessing the XMEGA NVM controller through the PDI interface, and executing NVM controller commands.

High-voltage serial programming HVSP [17] is mostly the backup mode on smaller AVRs. An 8-pin AVR package does not leave many unique signal combinations descargar play store market tablet place the AVR into a programming mode. A volt signal, however, is something the AVR should only see during programming and never during normal operation.

The high voltage mode can also be used in some devices where the reset pin has been disabled by fuses. High-voltage parallel programming HVPP is considered the "final resort" and may be the only way to correct bad fuse settings on an AVR chip. At reset, the bootloader runs first and does some user-programmed determination whether to re-program or to jump to the main application.

The code can re-program through any interface available, or it could read an encrypted binary through an Ethernet adapter like PXE.

Atmel has application notes and code pertaining to many bus interfaces. The AT90SC series of AVRs are available with a factory mask-ROM rather than flash for program memory.

The AVR offers several options for debugging, mostly involving on-chip debugging while the chip is in the target system. It is particularly useful for lower pin count parts which cannot provide the four "spare" pins needed for JTAG. The JTAGICE mkII, mkIII and the AVR Dragon support debugWIRE.

The Joint Ludacris shake your money maker album Action Group JTAG feature provides access to on-chip debugging functionality while the chip is running in the target system.

JTAG can also be used to perform a boundary scan test, [29] which tests the electrical connections between AVRs and other boundary scan capable chips in a system.

Boundary scan is well-suited for a production line, while the hobbyist is probably better off ps3 game trade in value futureshop with a multimeter or oscilloscope.

Official Atmel AVR development tools and evaluation kits contain a number of starter kits and debugging tools with support for most AVR devices:.

C-Programmierung mit AVR-GCC/ Register – Wikibooks, Sammlung freier Lehr-, Sach- und Fachbücher

The STK starter kit and development system is an update to the STK The base board is similar to the STK, in that it provides a power supply, clock, in-system programming, an RS port and a CAN Controller Area Network, an automotive standard port via DE9 connectors, and stake pins for all avr libc bit manipulation the GPIO signals from the target device.

The target boards have ZIF sockets for DIPSOICQFNor QFP packages, depending on the board. The signal routing board sits between the base board and the target board, and routes the signals to the proper pin on the device board. There are many different signal routing boards that could be used with a single target board, depending on what device is in the ZIF socket.

The STK allows in-system programming from the PC via USB, leaving the RS port available for the target microcontroller. A 4 pin header on the STK labeled 'RS spare' can connect any TTL level USART port on the chip to an onboard MAX chip to translate the signals to RS levels.

The RS signals are connected to the RX, TX, CTS, and RTS pins on the DB-9 connector. The STK starter kit and development system features ISP and high voltage programming HVP for all AVR devices, either directly or through extension boards. The board is fitted with DIP sockets for all AVRs available in DIP packages. The STK starter kit and development system has a DIP socket that can host an AVR chip in a 40, 20, or 8-pin package.

The chip can be programmed with a dongle connected to the parallel port. The AVRISP and AVRISP mkII are inexpensive tools allowing all AVRs to be programmed make fast money dead frontier ICSP.

The AVRISP connects to a PC via a serial port and draws power from the target system. The AVRISP allows using either of the "standard" ICSP pinouts, either the pin or 6-pin connector.

The AVRISP has been discontinued, replaced by the AVRISP mkII.

[TUT] [C] Bit manipulation (AKA "Programming ") | AVR Freaks

The AVRISP mkII connects to a PC via USB and draws power from USB. LEDs visible through the translucent case indicate the state of target power. In such occurrences, employee incentive stock option agreement programmer capable of sourcing greater current is required. The Atmel Dragon is an inexpensive tool which connects to a PC via USB.

bit manipulation - C syntax /AVR headers - Stack Overflow

The Dragon can program all AVRs via JTAG, HVP, PDI, [32] or ICSP. There is no area for any additional circuitry, although this can be provided by a third-party product called the "Dragon Rider". The JTAG In Circuit Emulator JTAGICE debugging tool supports on-chip debugging OCD of AVRs with a JTAG interface.

The original JTAGICE mkI uses an RS interface to a PC and can only program AVR's with a JTAG interface. The JTAGICE mkI is no longer in production, however it has been replaced by the JTAGICE mkII. The JTAGICE mkII debugging tool supports on-chip debugging OCD of AVRs with SPI, JTAG, PDI, and debugWIRE bric stock market integration in european. The debugWire interface enables debugging using only one pin the Reset pinallowing debugging of applications running on low pin-count microcontrollers.

The JTAGICE mkII connects using USB, but there is an alternate connection via a serial port, which requires using a separate power supply.

In addition to JTAG, the mkII supports ISP programming using 6-pin or pin adapters. Both the USB and serial links use a variant of the STK protocol. The JTAGICE3 updates the mkII with more advanced debugging capabilities and faster programming. It connects via USB and supports the JTAG, aWire, Caterpillar stock options, and PDI interfaces. It supports SPI, JTAG, PDI, and aWire programming modes and debugging using debugWIRE, JTAG, PDI, and aWire interfaces.

The very popular AVR Butterfly demonstration currency easy forex forex learn made trading trading is a self-contained, battery-powered computer running the Atmel AVR ATmegaV microcontroller.

It was built to show-off the AVR family, especially a then new built-in LCD interface. The board includes the LCD screen, joystick, speaker, serial port, real time clock RTCflash memory chip, and both temperature and voltage sensors.

Earlier versions of the AVR Butterfly also contained a CdS photoresistor ; it is not present on Butterfly boards produced after June to allow RoHS compliance. The AVR Butterfly comes preloaded with software to demonstrate the capabilities of the microcontroller. Factory firmware can scroll your name, display the sensor readings, and show the time. The AVR Butterfly also has a piezoelectric transducer that can be used to reproduce sounds and music. The AVR Butterfly demonstrates LCD driving by running a segment, six alpha-numeric character display.

A pre-installed bootloader program allows the board to be re-programmed via a standard RS serial plug with new programs that users can write with the free Atmel IDE tools. This small board, about half the size of a business card, is priced at slightly more than an AVR Butterfly. The board includes software, which lets it act as a USB mass storage device its documentation is shipped on the DataFlasha USB joystick, and more. To support the USB host capability, it must be operated from a battery, but when running as a USB peripheral, it only needs the power provided over USB.

Only the JTAG port uses conventional 2. The processor can also be programmed through USB from a Windows or Linux host, using the USB "Device Firmware Update" protocols. Atmel ships proprietary source code included but distribution restricted example programs and a USB protocol stack with the device. LUFA [38] is a third-party free software MIT license USB protocol stack for the USBKey and other 8-bit USB AVRs.

The RAVEN kit supports wireless development using Atmel's IEEE All these boards support JTAG-based development. The kit includes two AVR Raven boards, each with a 2. The radios are driven with ATmegap processors, which are supported by a custom segmented LCD display driven by an ATmegap processor.

Raven peripherals resemble the Butterfly: These are intended for use in developing remote sensor nodes, to control relays, or whatever is needed. The USB stick uses an AT90USB for connections to a USB host and to the 2. These are intended to monitor and control the remote nodes, relying on host power rather than local batteries. A wide variety of third-party programming and debugging tools are available for the AVR.

These devices use various interfaces, including RS, PC parallel port, and USB. AVRs have been used in various automotive applications such as security, safety, powertrain and entertainment systems. Atmel has recently launched a new publication "Atmel Automotive Compilation" to help developers with automotive applications. Some current usages are in BMW, Daimler-Chrysler and TRW.

The Arduino physical computing platform is based on an ATmega microcontroller ATmega or ATmega8 in board versions older than the Diecimila. The ATmega and ATmega, with more pinout and memory capabilities, have also been employed to develop the Arduino Mega platform. Arduino boards can be used with its language and IDEor with more conventional programming environments Cassembleretc. USB-based AVRs have been used in the Microsoft Xbox hand controllers.

The link between the controllers and Xbox is USB. Numerous companies produce AVR-based microcontroller boards intended for use by hobbyists, robot builders, experimenters and small system developers including: Cubloc, [40] gnusb, [41] BasicX, [42] Oak Micros, [43] ZX Microcontrollers, [44] and myAVR. Schneider Electric produces the M Motor and Motion Control Chip, incorporating an Atmel AVR Core and an advanced motion controller for use in a variety of motion applications.

With the growing popularity of FPGAs among the open source community, people have started developing open source processors compatible with the AVR instruction set. The OpenCores website lists the following major AVR clone projects:. In addition to the chips manufactured by Atmel, clones are available from LogicGreen Technologies.

Microcontrollers using the ATmega architecture are being manufactured by NIIET in VoroneshRussia, as part of the series of integrated circuits. This includes an ATmega under the designation VE7T Russian: From Wikipedia, the free encyclopedia. See templates for discussion to help reach a consensus.

Atmel AVR ATtiny comparison chart. Atmel AVR instruction set. Using the USI module for SPI communication" PDF. Retrieved 10 June Using the USI Module as a I 2 C Master" PDF. Using the USI module as a I 2 C slave" PDF. Half Duplex UART Using the USI Module" PDF. Retrieved 14 Jun The reset line has an internal pull-up resistor, but if the environment is noisy it can be insufficient and reset can therefore occur sporadically. Retrieved 13 January Getting started with XMEGA, page 7" PDF.

Retrieved 7 November Open Source USB Sensor Box". Schneider Electric Motion USA. Retrieved 29 March Single-board microcontroller Special function register. Am ARM Cortex-M AVR32 ColdFire CRX FR FR-V H8SX M32R MPC5xx PIC32 PowerPC Propeller TLCS TriCore V In-circuit serial programming ICSP In-system programming ISP Program and Debug Interface PDI High-voltage serial programming HVSP High voltage parallel programming HVPP Bootloader ROM aWire.

Embedded system Programmable logic controller. Reduced instruction set computer RISC architectures. Alpha AMD Am Apollo PRISM Atmel AVR32 Berkeley RISC Clipper CRISP DEC Prism Intel i Intel i MIPS-X Motorola PA-RISC ROMP Stanford MIPS.

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