text:
AVR microcontrollers

AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. 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 ROM, EPROM, or EEPROM used by other microcontrollers at the time.

AVR microcontrollers find many applications as embedded systems. They are especially common in hobbyist and educational embedded applications, popularized by their inclusion in many of the Arduino line of open hardware development boards.

History
The AVR architecture was conceived by two students at the Norwegian Institute of Technology (NTH), Alf-Egil Bogen and Vegard Wollan.

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. However, it is commonly accepted that AVR stands for Alf and Vegard's RISC processor. Note that the use of "AVR" in this article generally refers to the 8-bit RISC line of Atmel AVR microcontrollers.

The original AVR MCU was developed at a local ASIC house in Trondheim, Norway, called Nordic VLSI at the time, now Nordic Semiconductor, where Bogen and Wollan were working as students. It was known as a μRISC (Micro RISC) and was available as silicon IP/building block from Nordic VLSI. When the technology was sold to Atmel from Nordic VLSI, the internal architecture was further developed by Bogen and Wollan at Atmel Norway, a subsidiary of Atmel. The designers worked closely with compiler writers at IAR Systems to ensure that the AVR instruction set provided efficient compilation of high-level languages.

Among the first of the AVR line was the AT90S8515, which in a 40-pin DIP package has the same pinout as an 8051 microcontroller, including the external multiplexed address and data bus. The polarity of the RESET line was opposite (8051's having an active-high RESET, while the AVR has an active-low RESET ), but other than that the pinout was identical.

The AVR 8-bit microcontroller architecture was introduced in 1997. By 2003, Atmel had shipped 500 million AVR flash microcontrollers. The Arduino platform, developed for simple electronics projects, was released in 2005 and featured ATmega8 AVR microcontrollers.

Device overview
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.

Basic families
AVRs are generally classified into following:

tinyAVR – the ATtiny series

The ATtiny series features small package microcontrollers with a limited peripheral set available. However, the improved tinyAVR 0/1/2-series (released in 2016) include:
 * Peripherals equal to or exceed megaAVR 0-series
 * Event System
 * Improved AVRxt instruction set, hardware multiply

megaAVR – the ATmega series

The ATmega series features microcontrollers that provide an extended instruction set (multiply instructions and instructions for handling larger program memories), an extensive peripheral set, a solid amount of program memory, as well as a wide range of pins available. The megaAVR 0-series (released in 2016) also has functionality such as:
 * Event system
 * New peripherals with enhanced functionality
 * Improved AVRxt instruction set

AVR Dx – The AVR Dx family is featuring multiple microcontroller series, focused on HCI, analog signal conditioning and functional safety.

The parts numbers is formatted as AVRffDxpp, where ff is flash size, x is family, and pp is number of pins. Example: AVR128DA64 – 64-pin DA-series with 128k flash. All devices in the AVR Dx family include:
 * an Async Type D timer that can run faster than the CPU
 * 12-bit ADC
 * 10-bit DAC

 * AVR DA-series (early 2020) – The high memory density makes these MCUs well suited for both wired and wireless communication-stack-intensive functions.
 * integrated sensors for capacitative touch measurement (HCI)
 * offers the latest CIPs and a robust integrated analog portfolio
 * no external high frequency crystal

 * AVR DB-series (mid-late 2020) – inherits many features from the DA-family, while adding its own:
 * 2 or 3 on-chip opamps
 * MultiVoltage IO (MVIO) on PORTC
 * Supports external HF crystal

 * AVR DD-series (not yet released ) – small package microcontrollers designed to bring real-time control and multi-voltage operation to applications industrial control, home appliance products, automotive, and Internet of Things (IoT).
 * MVIO support on 3 or 4 pins

 * AVR EA-series (not yet released )
 * 8–64k flash
 * 28–48-pin package

XMEGA

the ATxmega series offers a wide variety of peripherals and functionality such as:
 * Extended performance features, such as DMA, "Event System", and cryptography support
 * Extensive peripheral set with ADCs

Application-specific AVR
 * megaAVRs with special features not found on the other members of the AVR family, such as LCD controller, USB controller, advanced PWM, CAN, etc.

FPSLIC (AVR with FPGA)
 * FPGA 5k to 40k gates
 * SRAM for the AVR program code, unlike all other AVRs
 * AVR core can run at up to 50 MHz

32-bit AVRs
 * In 2006, Atmel released microcontrollers based on the 32-bit AVR32 architecture. This was a completely different architecture unrelated to the 8-bit AVR, intended to compete with the ARM-based processors. It had a 32-bit data path, SIMD and DSP instructions, along with other audio- and video-processing features. The instruction set was similar to other RISC cores, but it was not compatible with the original AVR (nor any of the various ARM cores). Since then support for AVR32 has been dropped from Linux as of kernel 4.12; compiler support for the architecture in GCC was never mainlined into the compiler's central source-code repository and was available primarily in a vendor-supported fork. At the time that AVR32 was introduced, Atmel had already been a licensee of the ARM architecture, with both ARM7 and ARM9 microcontrollers having been released prior to and concurrently with the AVR32; later Atmel focused most development effort on 32-bit chips with ARM Cortex-M and Cortex-A cores.

Device architecture
The AVRs have 32 single-byte registers and are classified as 8-bit RISC devices.

Flash, EEPROM, and 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 memory
Program instructions are stored in non-volatile flash memory. Although the MCUs are 8-bit, each instruction takes one or two 16-bit words. The size of the program memory is usually indicated in the naming of the device itself (e.g., the ATmega64x line has 64 KB of flash, while the ATmega32x line has 32 KB). There is no provision for off-chip program memory; all code executed by the AVR core must reside in the on-chip flash. However, this limitation does not apply to the AT94 FPSLIC AVR/FPGA chips.

Internal data memory
The data address space consists of the register file, I/O registers, and SRAM. Some small models also map the program ROM into the data address space, but larger models do not.

Internal registers
In the tinyAVR and megaAVR variants of the AVR architecture, the working registers are mapped in as the first 32 data memory addresses (000016–001F16), followed by 64 I/O registers (002016–005F16). In devices with many peripherals, these registers are followed by 160 “extended I/O” registers, only accessible as memory-mapped I/O (006016–00FF16).

Actual SRAM starts after these register sections, at address 006016 or, in devices with "extended I/O", at 010016.

Even though there are separate addressing schemes and optimized opcodes for accessing the register file and the first 64 I/O registers, all can also be addressed and manipulated as if they were in SRAM.

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. I/O memory begins at address 000016, followed by SRAM. In addition, these devices have slight deviations from the standard AVR instruction set. Most notably, the direct load/store instructions (LDS/STS) have been reduced from 2 words (32 bits) to 1 word (16 bits), limiting the total direct addressable memory (the sum of both I/O and SRAM) to 128 bytes. Conversely, the indirect load instruction's (LD) 16-bit address space is expanded to also include non-volatile memory such as Flash and configuration bits; therefore, the Load Program Memory (LPM) instruction is unnecessary and omitted. (For detailed info, see Atmel AVR instruction set.)

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. Instead, the I/O registers are mapped into the data address space starting at the very beginning of the address space. Additionally, the amount of data address space dedicated to I/O registers has grown substantially to 4096 bytes (000016–0FFF16). As with previous generations, however, the fast I/O manipulation instructions can only reach the first 64 I/O register locations (the first 32 locations for bitwise instructions). Following the I/O registers, the XMEGA series sets aside a 4096 byte range of the data address space, which can be used optionally for mapping the internal EEPROM to the data address space (100016–1FFF16). The actual SRAM is located after these ranges, starting at 200016.

GPIO ports
Each GPIO port on a tiny or mega AVR drives up to eight pins and is controlled by three 8-bit registers: DDRx, PORTx and PINx, where x is the port identifier.

 * DDRx: Data Direction Register, configures the pins as either inputs or outputs.
 * PORTx: Output port register. Sets the output value on pins configured as outputs. Enables or disables the pull-up resistor on pins configured as inputs.
 * PINx: Input register, used to read an input signal. On some devices, this register can be used for pin toggling: writing a logic one to a PINx bit toggles the corresponding bit in PORTx, irrespective of the setting of the DDRx bit.

Newer ATtiny AVR's, like ATtiny817 and its siblings, have their port control registers somewhat differently defined. xmegaAVR have additional registers for push/pull, totem-pole and pullup configurations.

EEPROM
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. It can only be accessed the same way an external peripheral device is, using special pointer registers and read/write instructions, which makes EEPROM access much slower than other internal RAM.

However, some devices in the SecureAVR (AT90SC) family 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.

Since the number of writes to EEPROM is limited – Atmel specifies 100,000 write cycles in their datasheets –  a well designed EEPROM write routine should compare the contents of an EEPROM address with desired contents and only perform an actual write if the contents need to be changed.

Program execution
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.

Instruction set
The AVR instruction set is more orthogonal than those of most eight-bit microcontrollers, in particular the 8051 clones and PIC microcontrollers with which AVR competes today. However, it is not completely regular:

 * Pointer registers X, Y, and Z have addressing capabilities that are different from each other.
 * Register locations R0 to R15 have more limited addressing capabilities than register locations R16 to R31.
 * I/O ports 0 to 31 can be bit addressed, unlike I/O ports 32 to 63.
 * CLR (clear all bits to zero) affects flags, while SER (set all bits to one) does not, even though they are complementary instructions. (CLR is pseudo-op for EOR R, R; while SER is short for LDI R,$FF. Arithmetic operations such as EOR modify flags, while moves/loads/stores/branches such as LDI do not.)
 * Accessing read-only data stored in the program memory (flash) requires special LPM instructions; the flash bus is otherwise reserved for instruction memory.

Additionally, some chip-specific differences affect code generation. Code pointers (including return addresses on the stack) are two bytes long on chips with up to 128 KB of flash memory, but three bytes long on larger chips; not all chips have hardware multipliers; chips with over 8 KB of flash have branch and call instructions with longer ranges; and so forth.

The mostly regular instruction set makes C (and even Ada) compilers fairly straightforward and efficient. GCC has included AVR support for quite some time, and that support is widely used. LLVM also has rudimentary AVR support. 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.

MCU speed
The AVR line can normally support clock speeds from 0 to 20 MHz, with some devices reaching 32 MHz. 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 1024. This prescaler can be reconfigured by software during run-time, allowing the clock speed to be optimized.

Since all operations (excluding multiplication and 16-bit add/subtract) on registers R0–R31 are single-cycle, the AVR can achieve up to 1 MIPS per MHz, i.e. an 8 MHz processor can achieve up to 8 MIPS. Loads and stores to/from memory take two cycles, branching takes two cycles. Branches in the latest "3-byte PC" parts such as ATmega2560 are one cycle slower than on previous devices.

Development
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. Compatibility between chips in each family is fairly good, although I/O controller features may vary.

See external links for sites relating to AVR development.

Features
AVRs offer a wide range of features:

 * Multifunction, bi-directional general-purpose I/O ports with configurable, built-in pull-up resistors
 * Multiple internal oscillators, including RC oscillator without external parts
 * Internal, self-programmable instruction flash memory up to 256 KB (384 KB on XMega)
 * In-system programmable using serial/parallel low-voltage proprietary interfaces or JTAG
 * Optional boot code section with independent lock bits for protection
 * On-chip debugging (OCD) support through JTAG or debugWIRE on most devices
 * The JTAG signals (TMS, TDI, TDO, and TCK) are multiplexed on GPIOs. These pins can be configured to function as JTAG or GPIO depending on the setting of a fuse bit, which can be programmed via ISP or HVSP. By default, AVRs with JTAG come with the JTAG interface enabled.
 * debugWIRE uses the /RESET pin as a bi-directional communication channel to access on-chip debug circuitry. It is present on devices with lower pin counts, as it only requires one pin.
 * Internal data EEPROM up to 4 KB
 * Internal SRAM up to 16 KB (32 KB on XMega)
 * External 64 KB little endian data space on certain models, including the Mega8515 and Mega162.
 * The external data space is overlaid with the internal data space, such that the full 64 KB address space does not appear on the external bus and accesses to e.g. address 010016 will access internal RAM, not the external bus.
 * In certain members of the XMega series, the external data space has been enhanced to support both SRAM and SDRAM. As well, the data addressing modes have been expanded to allow up to 16 MB of data memory to be directly addressed.
 * 8-bit and 16-bit timers
 * PWM output (some devices have an enhanced PWM peripheral which includes a dead-time generator)
 * Input capture that record a time stamp triggered by a signal edge
 * Analog comparator
 * 10 or 12-bit A/D converters, with multiplex of up to 16 channels
 * 12-bit D/A converters
 * A variety of serial interfaces, including
 * I²C compatible Two-Wire Interface (TWI)
 * Synchronous/asynchronous serial peripherals (UART/USART) (used with RS-232, RS-485, and more)
 * Serial Peripheral Interface Bus (SPI)
 * Universal Serial Interface (USI): a multi-purpose hardware communication module that can be used to implement an SPI, I2C or UART interface.
 * Brownout detection
 * Watchdog timer (WDT)
 * Multiple power-saving sleep modes
 * Lighting and motor control (PWM-specific) controller models
 * CAN controller support
 * USB controller support
 * Proper full-speed (12 Mbit/s) hardware & Hub controller with embedded AVR.
 * Also freely available low-speed (1.5 Mbit/s) (HID) bitbanging software emulations
 * Ethernet controller support
 * LCD controller support
 * Low-voltage devices operating down to 1.8 V (to 0.7 V for parts with built-in DC–DC upconverter)
 * picoPower devices
 * DMA controllers and "event system" peripheral communication.
 * Fast cryptography support for AES and DES

Programming interfaces
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.

ISP
The in-system programming (ISP) programming method is functionally performed through SPI, plus 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-ICE device or AVRISP mkII (Legacy device) connects to a computer's USB port and performs in-system programming using Atmel's software.

AVRDUDE (AVR Downloader/UploaDEr) runs on Linux, FreeBSD, Windows, and Mac OS X, and supports a variety of in-system programming hardware, including Atmel AVRISP mkII, Atmel JTAG ICE, older Atmel serial-port based programmers, and various third-party and "do-it-yourself" programmers.

PDI
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. The PDI is a 2-pin interface using the Reset pin for clock input (PDI_CLK) and a dedicated data pin (PDI_DATA) for input and output.

UPDI
The Unified Program and Debug Interface (UPDI) is a one-wire interface for external programming and on-chip debugging of newer ATtiny and ATmega devices. The Atmel-ICE and PICkit 4 are capable of programming UPDI chips. It is also possible to use an Arduino thanks to jtag2updi, or a standard USB-UART adapter with the TX and RX pin shorted by a 1 kΩ resistor and the pymcuprog utility provided by Microchip.

High-voltage serial
High-voltage serial programming (HVSP) is mostly the backup mode on smaller AVRs. An 8-pin AVR package does not leave many unique signal combinations to place the AVR into a programming mode. A 12-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
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.

Bootloader
Most AVR models can reserve a bootloader region, 256 bytes to 4 KB, where re-programming code can reside. 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.

ROM
The AT90SC series of AVRs are available with a factory mask-ROM rather than flash for program memory. Because of the large up-front cost and minimum order quantity, a mask-ROM is only cost-effective for high-production runs.

aWire
aWire is a new one-wire debug interface available on the new UC3L AVR32 devices.

Debugging interfaces
The AVR offers several options for debugging, mostly involving on-chip debugging while the chip is in the target system.

debugWIRE
debugWIRE is Atmel's solution for providing on-chip debug capabilities via a single microcontroller pin. 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. debugWIRE was developed after the original JTAGICE release, and now clones support it.

JTAG
The Joint Test Action Group (JTAG) feature provides access to on-chip debugging functionality while the chip is running in the target system. JTAG allows accessing internal memory and registers, setting breakpoints on code, and single-stepping execution to observe system behaviour.

Atmel provides a series of JTAG adapters for the AVR:

 * 1) The Atmel-ICE is the latest adapter. It supports JTAG, debugWire, aWire, SPI, TPI, and PDI interfaces.
 * 2) The JTAGICE 3 is a midrange debugger in the JTAGICE family (JTAGICE mkIII). It supports JTAG, aWire, SPI, and PDI interfaces.
 * 3) The JTAGICE mkII replaces the JTAGICE and is similarly priced. The JTAGICE mkII interfaces to the PC via USB, and supports both JTAG and the newer debugWIRE interface. Numerous third-party clones of the Atmel JTAGICE mkII device started shipping after Atmel released the communication protocol.
 * 4) The AVR Dragon is a low-cost (approximately $50) substitute for the JTAGICE mkII for certain target parts. The AVR Dragon provides in-system serial programming, high-voltage serial programming and parallel programming, as well as JTAG or debugWIRE emulation for parts with 32 KB of program memory or less. ATMEL changed the debugging feature of AVR Dragon with the latest firmware of AVR Studio 4 - AVR Studio 5 and now it supports devices over 32 KB of program memory.
 * 5) The JTAGICE adapter interfaces to the PC via a standard serial port. Although the JTAGICE adapter has been declared "end-of-life" by Atmel, it is still supported in AVR Studio and other tools.

JTAG can also be used to perform a boundary scan test, 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 testing with a multimeter or oscilloscope.

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

STK600 starter kit
The STK600 starter kit and development system is an update to the STK500. The STK600 uses a base board, a signal routing board, and a target board.

The base board is similar to the STK500, in that it provides a power supply, clock, in-system programming, an RS-232 port and a CAN (Controller Area Network, an automotive standard) port via DE9 connectors, and stake pins for all of the GPIO signals from the target device.

The target boards have ZIF sockets for DIP, SOIC, QFN, or 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 STK600 allows in-system programming from the PC via USB, leaving the RS-232 port available for the target microcontroller. A 4 pin header on the STK600 labeled 'RS-232 spare' can connect any TTL level USART port on the chip to an onboard MAX232 chip to translate the signals to RS-232 levels. The RS-232 signals are connected to the RX, TX, CTS, and RTS pins on the DB-9 connector.

STK500 starter kit
The STK500 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.

STK500 Expansion Modules: Several expansion modules are available for the STK500 board:

 * STK501 – Adds support for microcontrollers in 64-pin TQFP packages.
 * STK502 – Adds support for LCD AVRs in 64-pin TQFP packages.
 * STK503 – Adds support for microcontrollers in 100-pin TQFP packages.
 * STK504 – Adds support for LCD AVRs in 100-pin TQFP packages.
 * STK505 – Adds support for 14 and 20-pin AVRs.
 * STK520 – Adds support for 14 and 20, and 32-pin microcontrollers from the AT90PWM and ATmega family.
 * STK524 – Adds support for the ATmega32M1/C1 32-pin CAN/LIN/Motor Control family.
 * STK525 – Adds support for the AT90USB microcontrollers in 64-pin TQFP packages.
 * STK526 – Adds support for the AT90USB microcontrollers in 32-pin TQFP packages.

STK200 starter kit
The STK200 starter kit and development system has a DIP socket that can host an AVR chip in a 40, 20, or 8-pin package. The board has a 4 MHz clock source, 8 light-emitting diode (LED)s, 8 input buttons, an RS-232 port, a socket for a 32 KB SRAM and numerous general I/O. The chip can be programmed with a dongle connected to the parallel port.

Atmel-ICE
The Atmel ICE is the currently supported inexpensive tool to program and debug all AVR devices (unlike the AVRISP/AVRISP mkII, Dragon, etc. discussed below). It connects to and receives power from a PC via USB, and supports JTAG, PDI, aWire, debugWIRE, SPI, SWD, TPI, and UPDI (the Microchip Unified Program and Debug Interface) interfaces.

The ICE can program and debug all AVRs via the JTAG interface, and program with additional interfaces as supported on each device:
 * 8-bit AVR XMEGA devices via the PDI 2-wire interface
 * 8-bit megaAVR and tinyAVR devices via SPI for all with OCD (on-chip debugger) support
 * 8-bit tinyAVR microcontrollers with TPI support
 * 32-bit SAM Arm Cortex-M based microcontrollers via SWD

Target operating voltage ranges of 1.62V to 5.5V are supported as well as the following clock ranges:
 * Supports JTAG & PDI clock frequencies from 32 kHz to 7.5 MHz
 * Supports aWire baud rates from 7.5 kbit/s to 7 Mbit/s
 * Supports debugWIRE baud rates from 4 kbit/s to 0.5 Mbit/s
 * Supports SPI clock frequencies from 8 kHz to 5 MHz
 * Supports SWD clock frequencies from 32 kHz to 2 MHz

The ICE is supported by the Microchip Studio IDE, as well as a command line interface (atprogram).

The Atmel-ICE supports a limited implementation of the Data Gateway Interface (DGI) when debugging and programming features are not in use. The Data Gateway Interface is an interface for streaming data from a target device to the connected computer. This is meant as a useful adjunct to the unit to allow for demonstration of application features and as an aid in application level debugging.

AVRISP and AVRISP mkII
The AVRISP and AVRISP mkII are inexpensive tools allowing all AVRs to be programmed via 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 10-pin or 6-pin connector.

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.

As the AVRISP mkII lacks driver/buffer ICs, it can have trouble programming target boards with multiple loads on its SPI lines. In such occurrences, a programmer capable of sourcing greater current is required. Alternatively, the AVRISP mkII can still be used if low-value (~150 ohm) load-limiting resistors can be placed on the SPI lines before each peripheral device.

Both the AVRISP and the AVRISP mkII are now discontinued, with product pages removed from the Microchip website. As of July 2019 the AVRISP mkII is still in stock at a number of distributors. There are also a number of 3rd party clones available.

AVR Dragon
The Atmel Dragon is an inexpensive tool which connects to a PC via USB. The Dragon can program all AVRs via JTAG, HVP, PDI, or ICSP. The Dragon also allows debugging of all AVRs via JTAG, PDI, or debugWire; a previous limitation to devices with 32 KB or less program memory has been removed in AVR Studio 4.18. The Dragon has a small prototype area which can accommodate an 8, 28, or 40-pin AVR, including connections to power and programming pins. There is no area for any additional circuitry, although this can be provided by a third-party product called the "Dragon Rider".

JTAGICE
The JTAG In Circuit Emulator (JTAGICE) debugging tool supports on-chip debugging (OCD) of AVRs with a JTAG interface. The original JTAGICE (sometimes retroactively referred to as JTAGICE mkI) uses an RS-232 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.

JTAGICE mkII
The JTAGICE mkII debugging tool supports on-chip debugging (OCD) of AVRs with SPI, JTAG, PDI, and debugWIRE interfaces. The debugWire interface enables debugging using only one pin (the Reset pin), allowing 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 10-pin adapters). Both the USB and serial links use a variant of the STK500 protocol.

JTAGICE3
The JTAGICE3 updates the mkII with more advanced debugging capabilities and faster programming. It connects via USB and supports the JTAG, aWire, SPI, and PDI interfaces. The kit includes several adapters for use with most interface pinouts.

AVR ONE!
The AVR ONE! is a professional development tool for all Atmel 8-bit and 32-bit AVR devices with On-Chip Debug capability. It supports SPI, JTAG, PDI, and aWire programming modes and debugging using debugWIRE, JTAG, PDI, and aWire interfaces.

Butterfly demonstration board

The very popular AVR Butterfly demonstration board is a self-contained, battery-powered computer running the Atmel AVR ATmega169V 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 (RTC), flash 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 2006 to allow RoHS compliance. The small board has a shirt pin on its back so it can be worn as a name badge.

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 14-segment, six alpha-numeric character display. However, the LCD interface consumes many of the I/O pins.

The Butterfly's ATmega169 CPU is capable of speeds up to 8 MHz, but it is factory set by software to 2 MHz to preserve the button battery life. A pre-installed bootloader program allows the board to be re-programmed via a standard RS-232 serial plug with new programs that users can write with the free Atmel IDE tools.

AT90USBKey
This small board, about half the size of a business card, is priced at slightly more than an AVR Butterfly. It includes an AT90USB1287 with USB On-The-Go (OTG) support, 16 MB of DataFlash, LEDs, a small joystick, and a temperature sensor. The board includes software, which lets it act as a USB mass storage device (its documentation is shipped on the DataFlash), a 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 2.54 mm pinout. All the other AVR I/O ports require more compact 1.27 mm headers.

The AVR Dragon can both program and debug since the 32 KB limitation was removed in AVR Studio 4.18, and the JTAGICE mkII is capable of both programming and debugging the processor. 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 is a third-party free software (MIT license) USB protocol stack for the USBKey and other 8-bit USB AVRs.

Raven wireless kit
The RAVEN kit supports wireless development using Atmel's IEEE 802.15.4 chipsets, for Zigbee and other wireless stacks. It resembles a pair of wireless more-powerful Butterfly cards, plus a wireless USBKey; and costing about that much (under $US100). All these boards support JTAG-based development.

The kit includes two AVR Raven boards, each with a 2.4 GHz transceiver supporting IEEE 802.15.4 (and a freely licensed Zigbee stack). The radios are driven with ATmega1284p processors, which are supported by a custom segmented LCD display driven by an ATmega3290p processor. Raven peripherals resemble the Butterfly: piezo speaker, DataFlash (bigger), external EEPROM, sensors, 32 kHz crystal for RTC, and so on. These are intended for use in developing remote sensor nodes, to control relays, or whatever is needed.

The USB stick uses an AT90USB1287 for connections to a USB host and to the 2.4 GHz wireless links. These are intended to monitor and control the remote nodes, relying on host power rather than local batteries.

Third-party programmers
A wide variety of third-party programming and debugging tools are available for the AVR. These devices use various interfaces, including RS-232, PC parallel port, and USB.

Uses

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 ATmega328 microcontroller (ATmega168 or ATmega8 in board versions older than the Diecimila). The ATmega1280 and ATmega2560, 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 IDE, or with more conventional programming environments (C, assembler, etc.) as just standardized and widely available AVR platforms.

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, gnusb, BasicX, Oak Micros, ZX Microcontrollers, and myAVR. There is also a large community of Arduino-compatible boards supporting similar users.

Schneider Electric used to produce the M3000 Motor and Motion Control Chip, incorporating an Atmel AVR Core and an advanced motion controller for use in a variety of motion applications but this has been discontinued.

FPGA clones
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:

 * pAVR, written in VHDL, is aimed at creating the fastest and maximally featured AVR processor, by implementing techniques not found in the original AVR processor such as deeper pipelining.
 * avr_core, written in VHDL, is a clone aimed at being as close as possible to the ATmega103.
 * Navré, written in Verilog, implements all Classic Core instructions and is aimed at high performance and low resource usage. It does not support interrupts.
 * softavrcore, written in Verilog, implements the AVR instruction set up to AVR5, supports interrupts along with optional automatic interrupt acknowledgement, power saving via sleep mode plus some peripheral interfaces and hardware accelerators (such as UART, SPI, cyclic redundancy check calculation unit and system timers). These peripherals demonstrate how could these be attached to and configured for this core. Within the package, a full-featured FreeRTOS port is also available as an example for the core + peripheral utilization.
 * The opencores project CPU lecture written in VHDL by Dr. Jürgen Sauermann explains in detail how to design a complete AVR-based system on a chip (SoC).

Other vendors
In addition to the chips manufactured by Atmel, clones are available from LogicGreen Technologies. These parts are not exact clones - they have a few features not found in the chips they are "clones" of, and higher maximum clock speeds, but use SWD (Serial Wire Debug, a variant of JTAG from ARM) instead of ISP for programming, so different programming tools must be used.

Microcontrollers using the ATmega architecture are being manufactured by NIIET in Voronezh, Russia, as part of the 1887 series of integrated circuits. This includes an ATmega128 under the designation 1887VE7T (1887ВЕ7Т).

title: AVR microcontrollers


text:
AVR

AVR may refer to:

Railroad

 * Allegheny Valley Railroad, shortline railroad in Pennsylvania, U.S.
 * Aroostook Valley Railroad, a defunct railroad in Maine, U.S.
 * Assiniboine Valley Railway, a minimum gauge railway in Winnipeg, Canada
 * Avon Valley Railway, a heritage railway in the United Kingdom

Radio

 * Aboriginal Voices Radio, an Aboriginal Canadian national radio network
 * Annapolis Valley Radio, a country station located in Kentville, Nova Scotia

Electronics

 * AVR microcontrollers, a family of microcontrollers originally developed by Atmel, now part of Microchip Technology
 * Audio/video receiver, a home theater electronic component
 * Acronym for augmented reality and virtual reality interactive experiences
 * Automatic voltage regulator

Other uses

 * Armed violence reduction
 * Aortic valve replacement
 * Automatic voter registration
 * Avacyn Restored
 * AVR reactor (Arbeitsgemeinschaft Versuchsreaktor), a German prototype pebble bed reactor
 * Avirulence gene, "Avr"
 * Auxiliary Vessel, Rescue or Aircraft Vessel, Rescue
 * Lead augmented vector right (aVR), a voltage difference in electrocardiography

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: AVR


text:
New Orleans Pelicans (baseball)

The New Orleans Pelicans or "Pels" were a minor league professional baseball team based in New Orleans, Louisiana.

History
Founded in 1865 as an amateur social/sporting organization, the Pelicans became a professional franchise when they joined the Southern League in 1887. That league operated off and on until it finally folded in 1899. During that time the team captured three pennants: 1887, 1889, and 1896. The Pelicans then became a founding member of the Southern Association in 1901. From 1887 to 1900, the team played at Sportsman's Park/Crescent City Base Ball Park located at the foot of Canal Street near the New Basin Canal (now the Pontchartrain Expressway).

In 1901, the Pelicans moved to Athletic Park and played there until 1908. After the 1908 season the team moved to Pelican Park, which was located on South Carrollton Avenue, across from present-day Jesuit High School. In 1914, the Pelican Park wooden grandstand was moved by mule teams a quarter-mile down South Carrollton Avenue to the intersection with Tulane Avenue in Mid-City New Orleans. From 1915 through 1936 the facility was known as Heinemann Park after Alexander J. Heinemann, a shareholder in the club and owner of the stadium. The name was changed in 1936 to Pelican Stadium following the death of Heinemann and team owner Charles Somers. The Pelicans played their final game there in 1957. After this, they played for two years at City Park Stadium, now called Tad Gormley Stadium, in City Park. The franchise was sold to Little Rock at the end of the 1959 season. The Southern Association folded after the 1961 season.

The Pelicans won the Dixie Series, a postseason interleague championship between the champions of the Southern Association and the Texas League, in 1933 and 1934.

Notable Pelicans included Shoeless Joe Jackson, Jimmy Dygert, Henry "Cotton" Knaupp, Bill Lindsay, Zeke Bonura, Gene Freese, and Hall of Famers Dazzy Vance, Joe Sewell, Bob Lemon, and Earl Weaver. In Jackson's only season with New Orleans (1910), he hit .354 to win the league batting title and led the team to the pennant with an 87–53 record. The following year, he would hit .408 with the American League's Cleveland Naps.

In the 1950s, the team was associated with the Pittsburgh Pirates and was managed by Danny Murtaugh. Other notable Pelican managers included Larry Gilbert and Abner Powell, with the latter credited with introducing the perforated "rain check" in 1889.

The Pelicans' name briefly resurfaced during the 1977 season when oilman A. Ray Smith moved his Triple-A Tulsa Oilers to New Orleans to play in the Superdome. Tony La Russa was a reserve infielder for the team, playing most of his games at 2nd base. After a single season, the team then moved to Springfield, Illinois, and was renamed the Redbirds.

Name revival
On December 4, 2012, it was reported that Tom Benson, owner of the NFL's New Orleans Saints and the NBA's New Orleans Hornets, would be changing the Hornets' official name to the Pelicans, possibly as early as the 2013–2014 NBA season.

These reports were officially confirmed on January 24, 2013, when the newly branded Pelicans officially announced the name change and unveiled accompanying logos and a blue, gold and red color scheme. One year later, the Hornets name, logo and color scheme were reclaimed by the now Charlotte Hornets. The basketball Hornets originally came from Charlotte, North Carolina, before relocating to New Orleans in 2002.

Affiliations
The Pelicans were affiliated with the following major league teams:

title: New Orleans Pelicans (baseball)


text:
Mouride

The Mouride brotherhood (yoonu murit, الطريقة المريدية aṭ-Ṭarīqat al-Murīdiyyah or simply المريدية, al-Murīdiyyah) is a large tariqa (Sufi order) most prominent in Senegal and The Gambia with headquarters in the city of Touba, which is a holy city for the order. Adherents are called Mourides, from the Arabic word murīd (literally "one who desires"), a term used generally in Sufism to designate a disciple of a spiritual guide.The beliefs and practices of the Mourides constitute Mouridism. Mouride disciples call themselves taalibé in Wolof and must undergo a ritual of allegiance called njebbel, as it is considered highly important to have a sheikh "spiritual guide" in order to become a Mouride. The Mouride brotherhood was founded in 1883 in Senegal by Amadou Bamba. The Mouride make up around 40 percent of the total population, and their influence over everyday life can be seen throughout Senegal.

Cheikh Ahmadou Bamba Mbacké Khadimou Rassoul
The Mouride brotherhood was founded in 1883 in Senegal by Shaykh Aḥmadu Bàmba Mbàkke (Wolof name), commonly known as Amadou Bamba (1850–1927). In Arabic, he is known as Aḥmad ibn Muhammad ibn Habīb Allāh or by the nickname "Khadīmu r-Rasūl" ("Servant of the Prophet"). In Wolof he is called "Sëriñ Tuubaa" ("Holy Man of Touba"). He was born in the village of Mbacké in Baol, the son of a Cheikh from the Qadiriyya, the oldest of the Muslim brotherhoods in Senegal.

Amadou Bamba was a Muslim mystic and ascetic marabout, a spiritual leader who wrote tracts on meditation, rituals, work, and tafsir. He is perhaps best known for his emphasis on work, and his disciples are known for their industriousness. Although he did not support the French conquest of West Africa, he did not wage outright war on them, as several prominent Tijani cheikh had done. He taught, instead, what he called the jihād al-akbar or "greater struggle," which fought not through weapons but through learning and fear of God.

Bamba's followers call him a mujaddid (a "renewer of Islam"). Bamba's fame spread through his followers, and people joined him to receive the salvation that he promised. Salvation, he said, comes through submission to the cheikh and hard work.

There is only one surviving photograph of Amadou Bamba, in which he wears a flowing white kaftan and his face is mostly covered by a scarf. This picture is venerated and reproduced in paintings on walls, buses, taxis, and other private and public spaces all over modern-day Senegal.

French colonial rule
At the time of the foundation of the Mouride brotherhood in 1883, the French were in control of Senegal as well as most of West and North Africa. Although it had shared in the horrors of the pre-colonial slave trade, French West Africa was managed relatively better than other African regions during the Scramble for Africa and ensuing colonial era. Senegal enjoyed small measures of self-rule in many areas. However, French rule still discouraged the development of local industry, preferring to force the exchange of raw materials for European finished goods, and a large number of taxation measures were instituted.

At the end of the 19th century, French colonial authorities began to worry about the growing power of the Mouride brotherhood and its potential to resist French colonialism. Bamba, who had converted various kings and their followers, could probably have raised an army against the French had he wanted. Fearful of his power, the French sentenced Bamba to exile in Gabon (1895–1902) and later Mauritania (1903–1907) and confining him in house arrest in Senegal until 1912.

However, Bamba's exile fueled legends about his miraculous ability to survive torture, deprivation, and attempted executions, and thousands more flocked to his organization. For example, on the ship to Gabon, forbidden from praying, Bamba is said to have broken his leg-irons, leapt overboard into the ocean, and prayed on a prayer rug that miraculously appeared on the surface of the water. In addition, when the French put him in a furnace, he is said to have simply sat down and had tea with Muhammad. In a den of hungry lions, it is said the lions slept beside him.

By 1912, policy shifted towards using the Senegalese Sufi orders – among them the Mourides – as assets in the colonial administration. This way, it was thought, the authority and power of the orders could instead be used to support colonial rule. In order to facilitate rapprochement and in an attempt to limit the appearance of Bamba as a freedom fighter, he was released from house arrest and moved back to Diourbel, close to the future site of Touba. The Mouride doctrine of hard work served French economic interests, as addressed below. After World War I, the Mouride brotherhood was allowed to grow and in 1926 Bamba began work on the Great Mosque in Touba, where he would be buried one year later.

Bamba’s successors were increasingly cordial with the French administration, collaborating and receiving support against rivals and material benefits such as land and machinery in return. This led to the brotherhood’s authority becoming part of a form of indirect rule by the French. In 1928 the French colonial administration issued a deed recognizing the land of Bamba’s tomb and the Great Mosque as private property of the Mouride community. This marked the first step towards Touba’s autonomy from the wider Senegalese state which continued post-independence.

The Mourides played a central role in the 1958 Senegalese constitutional referendum which determined whether Senegal would become part of the new French Community. The leaders of the main Senegalese Sufi orders jointly announced their loyalty to Charles de Gaulle and their support of the proposed French Community. Their campaigning, supported by the French Administration, led to the overwhelming yes of nearly 98% being coined “the marabouts’ Yes.”

Leadership
Shaikh Amadou Bamba was buried in 1927 at the Great Mosque in Touba, the holy city of Mouridism and the heart of the Mouride movement. After his death Bamba has been succeeded by his descendants as hereditary leaders of the brotherhood. The caliph (leader) of the Mouride brotherhood is known as the Grand Marabout and has his seat in Touba. The first five caliphs were all sons of Amadou Bamba, starting with his eldest son:

 * 1) Serigne Mouhamadou Moustapha Mbacké, caliph from 1927 to 1945
 * 2) Serigne Mouhamadou Fallilou Mbacké, caliph from 1945 to 1968
 * 3) Serigne Abdou Ahad Mbacké, caliph from 1968 to 1989
 * 4) Serigne Abdou Khadr Mbacké, caliph from 1989 to 1990
 * 5) Serigne Saliou Mbacké (1915-2007), caliph from 1990 until his death on December 28, 2007
 * 6) Serigne Mouhamadou Lamine Bara Mbacké, (1925–2010), caliph from 2007 to 2010. He was the first grandson of Ahmadou Bamba to become caliph.
 * 7) Serigne Sidi Moukhtar Mbacké, caliph from July 1, 2010 until his death on January 9, 2018.
 * 8) Serigne Mountakha Mbacké, incumbent caliph since January 10, 2018.

The Grand Marabout is a direct descendant of Amadou Bamba himself and is considered the spiritual leader of all Mourides. There are other marabouts, each with a regional following.

Dahiras
Dahiras are a unique institution of the Senegalese Sufi model which connect followers of a particular marabout or order in an association. They are often based on shared allegiances to a particular marabout or common geographical location, for example, a neighborhood or city-specific dahira. Other dahiras bring together followers belonging to the same age, gender, occupation, or school, linking them across Senegal and even abroad. A key example of this is the Hizbut-Tarqiyyah, which brought together Mouride students and alumni of the University of Dakar. Notably many Mouride dahiras name the Grand Marabout as their patron and thereby avoid allegiance to a specific marabout inside the order.

Dahiras first appeared in urban areas as religious solidarity and mutual aid groups to tackle the issues of urban migrants but have since spread across the country to rural areas as well. Next to providing a community of like-minded Mourides, they help facilitate the participation of members at important festivals and help raise funds for sudden expenses which individuals may be unable to cover themselves, such as funeral costs.

Daaras
Daaras are madrassas or Quranic schools. They were originally founded by the shaykh, his descendants, or disciples to teach the Quran and the khassida (or xassida, poems honoring Muhammad) as well as cultivating the land. Hence they have grown to be associations of Mourides, generally based on shared allegiance to a particular marabout.

Baye Fall

One famous disciple of Bamba, Ibrahima Fall, was known for his dedication to God and considered work as a form of adoration. Fall was the one to introduce the conduct with which a disciple should interact with his Shaykh, based on the example of the Sahabas and concepts presented in the 49th chapter of the Quran Al-Hujurat. Ibrahima Fall was responsible for guiding many of Bamba's more eccentric followers and new converts to Islam. His followers were the precursor to a subgroup of the Mouride brotherhood today referred to as the Baye Fall (Baay Faal), many of whom substitute hard labor and dedication to their marabout for the usual Muslim pieties.

Sheikh Ibrahima Fall was one of the first of Amadou Bamba's disciples and one of the most illustrious. He catalysed the Mouride movement and led all the labour work in the Mouride brotherhood. Fall reshaped the relation between Mouride talibes (disciples) and their guide, Amadou Bamba. Fall instituted the culture of work among Mourides with his concept of Dieuf Dieul, ("you reap what you sow"). Ibra Fall helped Amadou Bamba to expand Mouridism, in particular with Fall's establishment of the Baye Fall movement. For this contribution, Serigne Fallou, the second Caliph (leader) after Amadou Bamba, named him "Lamp Fall" (the light of Mouridism). In addition, Ibrahima Fall earned the title باب المريدين Bab al-Murīdīna, "Gate of the Mourides."

The members of the Baye Fall dress in colorful ragged clothes, wear their hair in dreadlocks which are called ndiange ("strong hair"), which they decorate usually with homemade beads, wire or string. They also carry clubs, and act as security guards in the annual Grand Magal pilgrimages to Touba. Women usually are covered in draping coverings including their heads and occasionally are known to wear highly decorative handmade jewelry made from household or natural items. In modern times the hard labor is often replaced by members roaming the streets asking for financial donations for their marabout. Several Baye Fall are talented musicians. A prominent member of the Baye Fall is the Senegalese musician Cheikh Lô.

The Three Pillars of Mouridism
Cheikh Ahmadou Bamba taught the Three Pillars of Mouridism: In summary, a Mouride aspires to achieve Islam by following the basic recommendations of Shariat. This includes (but is not limited to) performing individual obligations (Fard Ayn) such as prayer, ablution, fasting, pilgrimage and giving charity. A Mouride aspires to achieve Iman by the Six Articles of Faith: Belief in God, his angels, the prophets, the revealed Holy Books, the Day of Judgment and the Divine Decree. A Mouride aspires to achieve Ihsan by the path of Tasawwuf (Sufism) through taking initiation (Bayat) with a Sheikh of the Tariqat.
 * Islam by Fiqh
 * Iman by The Six Articles of Faith
 * Ihsan by Tasawwuf (Sufism)

The Mouride Triangle
Additionally to the Three Pillars of Mouridism, the Mourides follow what is called the Mouride Triangle:
 * Love: Love for Allâh and his Cheikhs
 * Service: Work for Allâh and service for humanity
 * Knowledge: With Love and Work over time follows divine light of Allah and knowledge directly to the heart

Renewer of Islam (Mujaddid)
Amadou Bamba is considered a mujaddid (renewer of Islam) by his followers, citing a hadith that implies that God will send renewers of the faith every 100 years. The members of all the Senegalese brotherhoods claim that their founders were such renewers. The Mouride beliefs are based on Quranic and Sufi traditions and influenced by the Qadiri and Tijani brotherhoods, as well as the works by the scholar al-Ghazali. Amadou Bamba wrote more than 1000 books in Classical Arabic, all of which are based on the Quran and Hadith. Ahmadou Bamba said "If it's not in the Qur'an or Hadith, it's not from me". Mourides sometimes call their order the "Way of Imitation of the Prophet". Parents sometimes send their sons to live with the marabout as talibes rather than giving them a conventional education. These boys receive Islamic training and are instilled with the doctrine of hard work.

Many Mourides consider the city of Touba as equally or even more important than Mecca. Pilgrims regularly come to Touba all year round, but the peak of the year is a mass pilgrimage called the Grand Màgal, which celebrates Bamba's return from exile.

Relationship with Reform Movement
As in other parts of West Africa and the wider Muslim world, the return of students from the Salafist and Wahhabist-influenced Islamic universities in the Middle East brought a new Islamic Reform movement to Senegal post-Second World War. As these movements rejected many of the Sufi traditions and foundations that marked Islam in West Africa, and had been linked to the idea of an “Islam noir” by French colonial administrators, they opposed the marabouts, their cooperation with the French colonial system, and their authoritarian position inside Senegal’s religious system. The Mourides’ strong economic position and political influence (see below), system of unconditional submission to their marabouts, and focus on labour over prayer, made them a natural target of the reformers. The importance of marabouts and saints in Mouride thought was seen as shirk. This also extended to locations, with reformers opposing the central role of the holy city of Touba and the Mouride tradition of spending significant amounts of money to transport dead relatives to be buried in the city. On a more popular level, the eccentricities of the Baye Fall have also been associated with the Mourides as a whole and been used to criticise them by various non-Mourides.

However, the central role of Mourides in Senegal has meant that even some Salafist-inspired reform movements have, over time, softened anti-maraboutic stances in order to focus on other issues, at times even cooperating with notable Mourides in order to gain popular support and pursue goals appealing to most Muslims. Other types of reform have come from inside the Mouride order, with younger marabouts drawing inspirations from reformists and West African Pentecostalism. They combine these inspirations with aspects of traditional Mouride beliefs, offering new forms of worship removed from the gerontocratic traditional order and incorporating modern media while calling for a return to a mythologised Mouride past of rejecting authority. These interactions and new movements highlight Islamic Studies professor Rüdiger Seeseman’s argument that rather than treating Sufism and reform Islam as unchanging and opposed, these movements interact and lead to new forms of thoughts which incorporate beliefs to best address the situations they find themselves in.

Political influence
The Mourides have wielded significant political influence on the national and local scale for most of their history. In a 1965 survey, elite Senegalese named Mouride Grand Marabout Fallilou Mbacké as the second most influential person in the country. Since then, the order has been described as having played a major role in fostering consent for government policies, and as being important political power brokers. As part of the njebbel, a loyal Mouride is ideologically required to follow his religious leaders’ instructions or risk of losing any material support that would have been given to him if he disregards them.

Marabouts very rarely themselves participate directly in the political process. What is more common is to see them exert their influence over their followers and use this in return to gain a larger presence in the Senegalese politics. Such things as withholding seed from granaries, unless followers purchase party cards, is a way that some marabouts exert their influence in the region to attain votes. Other marabout may actually seek out political office, but most prefer to use their influence as an intermediary of politics in Senegal.

As noted above, following a period of repression,, French colonial administrators recognized that the Mouride brotherhood was well-respected among the Senegalese and partnered with them to promote political and social order. Traditional Wolof aristocrats had proven problematic as intermediaries for the colonial authorities, and they hoped that Mouride leaders would be more effective and legitimate. During the French colonial reign, the marabouts usually gave their support to politicians based upon their support of the brotherhood's leaders and interests. The most notable of these was Blaise Diagne, whose successful campaign to the Chamber of Deputies in 1914 they subsidized. Together with the continued cooperation with the colonial administration, this successful partnership built the foundation for the future cooperation between the Senegalese government and the Mouride brotherhood. This was further strengthened by the close alliance with Léopold Senghor, who had courted the Mourides and other Sufi orders from early on. Senghor campaigned on stabilizing the price of groundnuts, vital to Mouride economic interests (see below) and promised to subsidize the completion of the Grand Mosque of Touba. In this way Senghor gained the electoral support of the Mourides while the order and the Grand Marabout benefitted from investments in Touba’s infrastructure and the symbolic power of state support.

After universal suffrage was given in 1956, Senegal saw a rapid increase in the number of voters, almost triple the number just 10 years prior. This swift increase meant more power for the marabout whose outreach spread largely over the rural and peasant communities, which now had the opportunity to vote. Because of the 'marabouts' far reaching influence in Senegal, politicians made a considerable effort to attain the support from these religious leaders for their personal advancement.

In order to attain their support in elections, bribes and material incentives were given to marabouts from political parties and potential candidates. Many believed that no party could hope to attain political power if the marabouts were completely opposed to it, and any party who rose to power had to comply with the Marabout's demands or lose their political support.

In the 1962 power clash between now-President Senghor and Prime Minister Mamadou Dia, the Mourides again played a notable role. Dia was supported by Salafiyya-inspired urban Reform movements which opposed the Mourdides’ collaboration with the colonial system and maraboutic influence. In line with these concerns, Dia had previously opposed the marabouts’ political influence through a number of agricultural reforms. Mouride leaders’ support lay squarely with Senghor, and Dia could muster little popular support among the rural population who followed their marabouts’ loyalties. This unwavering support of Senghor continued until Fallilou Mbacké’s death in 1968, after which relations with the government cooled.

Support for the government returned with Senghor’s successor Adbou Diouf in 1980, who again allocated funds to infrastructure projects in Touba and afforded the city more autonomy. While the effects of this are contested, the Grand Marabout did issue a forceful njebbel in support of Diouf for the 1988 elections, according to which failure to vote for him amounted to betrayal of Cheick Amadou Bamba’s will. However, this move was unpopular with many Mourides, and later led to a retreat from national politics by the position of the Grand Marabout.

The public perception of Mourides’ involvement in the highest level of politics changed with the election of Abdoulaye Wade in 2000. A devout Mouride, Wade travelled to Touba the day after his election to seek the blessing of the Grand Marabout, Serigne Saliou Mbacké. Wade pledged financial support for the Mourides and included notable Mourides in his government, securing public support of notable Mourides – however not that of the Grand Marabout. This support allowed Wade to cultivate the Mourides as a solid bloc of support.

The Party for Truth and Development, founded by Cheikh Ahmadou Kara Mbacké, a descendant of Cheick Amadou Bamba, marked the entry of an explicitly Mouride organisation into organised politics, with Kara reportedly also targeting a presidential run but being discouraged by his relatives.

Economic influence
Groundnuts are the third largest export from Senegal after fish and phosphates. The amount of groundnut crop which the Mourides produce has been estimated to range from one-third to three-quarters of Senegalese groundnut production, although others have now estimated it to equal around one-half of the national total of groundnuts produced. This partnership between the Brotherhood and the government stems from the French colonial administrators, who had viewed the production of groundnuts by the Mourides as a means of economic advantage through the increasing production of crops for export.

Due to this high proportion of groundnut crop produced by the Mouride, the brotherhood has always seemed to have a large influence in the groundnut market and the economy. Economic involvement is in fact encouraged by the religious leaders to their disciples through the use of ideology that places great value on the production labor which is performed in the service of God. Thus the Mourides devoted themselves to prayer and unpaid agricultural labor in service to their religious leaders. They cultivated the marabout's fields for a decade, and then returned all land profits earned from the groundnut production. After ten years of dedicated work, laborers then received a share of land (large estates were divided up among the laborers). They continued to turn a share of their agricultural output over to their spiritual guide, as groundnut production was the community's only means of sustenance.

The large share of the Mouride's control over the groundnut production has placed them in the center of the nation's economy. The government's economic planners in turn have kept the brotherhood in their minds when establishing policies about groundnut production. Although the government places an importance on the Mouride cultivators, the disciples do not have efficient ways of cultivating groundnuts, and their techniques are often destructive to the land. Rather than looking out for the best use of the land, the Mouride cultivators are more interested in a fast payback. The methods used by the marabout have led to a constant depletion of the forests in Senegal and have taken much of the nutrients out of the soil. Government agencies have made attempts to help the marabout become more efficient in groundnut production, such as providing incentives for the workers to slow down their production.

Because of their emphasis on work, the Mouride brotherhood is economically well-established in parts of Africa, especially in Senegal and the Gambia. In Senegal, the brotherhood controls significant sections of the nation's economy, for example the transportation sector and the peanut plantations. Ordinary followers donate part of their income to the Mouridiya.

Cultural influence
Islam is central to the political sociology of Senegal: the religious elite carry great weight in national politics; political discourse is replete with references and appeals to Islam. There is virtually no opposition to the principle of the secular state, socio-political cleavages based on religion, whether between Muslim and non-Muslim or between Sufi orders, are also virtually non-existent. Within Muslim discourse we find constant reference to such concepts as Islamic government, Islamic economics, or Islamic social order. The essential Islamic core lies in the shared belief in the fundamental unity of the Muslim world. The sense of belonging to a larger community, felt by many Muslims, is reinforced by the common use of Arabic as the language of prayer and religious learning.

Islam is a powerful mobilization instrument and provides the rhetoric for the formulation of ideological movements, and serves as a force for mobilizing people in the pursuit of goals defined by those movements. The role of local Islamic social structures, the nature of leadership and the relations between leaders and followers, the nature and sources of power and authority and the limits and constraints of the economy are all factors, which mediate and direct the impact of Islam on Politics. Senegalese elites have not found appeals to ethnic solidarity a productive means of building a mass following. Common religious affiliation has played a role in defusing the potential for tensions that arise from other social cleavages. There however remains a potential for ethnic and caste divides to enter the Senegalese socio-political organization.

The Senegalese have a mystical aspect to Islam, much like other Sufism brotherhoods. In Senegal, Islamic practice usually requires membership in religious brotherhoods that are dedicated to the marabouts of these groups. Marabouts are believed to be the mediators between Allah and the people. The people seek the help of marabouts for protection from the evil spirits, to improve one's status (in terms of career, love or relationship, finances etc.), to obtain a cure or remedy for sickness, or even to curse an enemy. Marabouts are believed to have the ability to deal with the spirit world and seek the spirits’ help in things impossible for humans. The spirits’ help is sought since they are thought to be a source of much baraka "blessings, divine grace".

The marabouts of the Mouride Brotherhood devote less time to study and teaching than other brotherhoods. They devote most of their time to ordering their disciples’ work and making amulets for their disciples' work and making amulets for their followers. Devout Mourides’ homes and workplaces are covered with pictures and sayings of their marabout, and they wear numerous amulets prepared by them. These acts are believed to bring them a better life and solve their problems as well. Even taxi and bus drivers fill their vehicles with stickers, paintings and photos of the marabouts of their particular brotherhoods.

The marabout-talibe relationship in Senegal is essentially a relationship of personal dependence. It can be a charismatic or a clientelistic relationship. In a charismatic relationship demonstrations of devotion and abnegation towards the marabouts can only explained because their talibes see them as intercessors or even intermediaries with god. This charismatic relationship is reinforced and complemented by a parallel clientelistic relationship between marabout and follower. The results is that marabouts are expected to provide certain material benefits to their follower in addition to the spiritual ones.

This patronage function has been important in the distribution of land, especially during periods of expanding peanut cultivation. Mouride social organization was developed in the context of the expanding peanut economy and its unique formulation was adapted to the economic imperatives of that context. The most distinctive institutional expression of Mouride agro-religious innovation is the daara, an agricultural community of young men in the service of a marabout. These collective farms were largely responsible for the expansion of peanut cultivation. A Mouride peasant may submit to a marabout's organization of agricultural work because it is the best option available to him, independently of the ideology which supports it.

In contrast to a vision of masses blindly manipulated by a religious elite, the ties of talibes to their marabouts are frequently far more contingent and tenuous than assumed. As a result, marabouts confront the problem of recruiting and retaining followers. People at times confront a choice of which marabout to follow, the level of attachment to that marabout, and the domains or situations in which to follow him. While there is a widespread belief in the marabout system in Senegal and a strong commitment to it, it is not necessarily accompanied by an absolute attachment to any one living marabout.

Influence outside Senegal
The brotherhood has a sizable representation in certain large cities in Europe and the United States. Most of these cities with a large Senegalese immigrant population have a Keur Serigne Touba (Residence of the Master of Touba), a seat for the community which accommodates meetings and prayers while also being used as a provisional residence for newcomers. In Paris and New York City, a number of the Mouride followers are small-scale street merchants. They often send money back to the brotherhood leaders in Touba.

In 2004 Senegalese musician Youssou N'Dour released his Grammy Award winning album Egypt, which documents his Mouride beliefs and retells the story of Amadou Bamba and the Mouridiya. His intent was devotional, and the album was received that way in the West, but local some Mourides mistook "Egypt" for pop music using Islamic prayers, and initially expressed displeasure, which frustrated Youssou.

title: Mouride