The AVR Butterfly is a battery-powered

single-board microcontroller A single-board microcontroller is a microcontroller built onto a single printed circuit board. This board provides all of the circuitry necessary for a useful control task: a microprocessor, I/O circuits, a clock generator, RAM, stored program ...

developed by

Atmel Atmel Corporation was a creator and manufacturer of semiconductors before being subsumed by Microchip Technology in 2016. Atmel was founded in 1984. The company focused on embedded systems built around microcontrollers. Its products included micr ...

. It consists of an Atmel ATmega169PV

Microcontroller A microcontroller (MCU for ''microcontroller unit'', often also MC, UC, or μC) is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable i ...

, a

liquid crystal display A liquid-crystal display (LCD) is a flat panel display, flat-panel display or other Electro-optic modulator, electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liqui ...

joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...

, speaker, serial port, real-time clock (RTC), internal

flash memory Flash memory is an electronic non-volatile computer memory storage medium that can be electrically erased and reprogrammed. The two main types of flash memory, NOR flash and NAND flash, are named for the NOR and NAND logic gates. Both us ...

, and sensors for temperature and voltage. The board is the size of a name tag and has a clothing pin on back so it can be worn as such after the user enters their name onto the LCD.

Feature set

LCD

The AVRButterfly demonstrates

LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...

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

CPU & Speed

The Butterfly's ATmega169 CPU is capable of speeds up to 8 MHz, however it is factory set by software to 2 MHz to preserve the button battery life. There are free replacement bootloaders available that will launch programs at 1, 2, 4 or 8 MHz speeds. Alternatively, this may be accomplished by changing the CPU prescaler in the application code.

Features

* ATmega169V AVR 8-bit CPU, including 16 Kbyte of Flash memory for code storage and 512 bytes of

EEPROM EEPROM (also called E2PROM) stands for electrically erasable programmable read-only memory and is a type of non-volatile memory used in computers, usually integrated in microcontrollers such as smart cards and remote keyless systems, or as a ...

for data storage * 100-segment LCD (without backlight) * 4-

Mbit The megabit is a multiple of the unit bit for digital information. The prefix mega (symbol M) is defined in the International System of Units (SI) as a multiplier of 106 (1 million), and therefore :1 megabit = = = 1000 kilobits. The megabit h ...

(512-Kbyte) AT45 flash memory * 4-way Mini-Joystick with center push-button * Light, temperature, and voltage (0-5 V range) sensors (light sensor no longer included due to the

RoHS directive The Restriction of Hazardous Substances Directive 2002/95/EC (RoHS 1), short for Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment, was adopted in February 2003 by the European Unio ...

) * Piezo speaker * Solder pads for user-supplied connectors: 2 8-bit I/O ports, ISP, USI,

JTAG JTAG (named after the Joint Test Action Group which codified it) is an Technical standard, industry standard for verifying designs and testing printed circuit boards after manufacture. JTAG implements standards for on-chip instrumentation in ele ...

* RS232 level converter & interface (Cable and connector provided by end user) * 3 V battery holder (CR2450 battery included)

Software

The Butterfly comes preloaded with software that demonstrates many features of the ATmega169, including reading of the ambient light level and temperature and playback of musical notes. The device has a clothing-pin attached to the back, so it may be worn as a name tag — the "name" may be entered via the joystick or over the RS-232 port, and will scroll across the LCD.

Reprogramming

The Butterfly can be freely reprogrammed using the same toolchains as for many other AVR controllers, for example using the

Atmel AVR AVR is a family of microcontrollers developed since 1996 by Atmel, acquired by Microchip Technology in 2016. These are modified Harvard architecture 8-bit Reduced instruction set computer, RISC single-chip microcontrollers. AVR was one of the f ...

assembly language or the free integrated development environment (IDE) ''Atmel Studio'' for programming in C. A pre-installed bootloader allows the board to be re-programmed with a standard RS-232 serial port, requiring no special hardware. The board also has ISP and

ports for in-circuit programming and debugging. All of these interfaces are implemented only as open soldering points, so the addition of some hardware is necessary to make them usable.

Butterfly projects and applications

Several projects have been built using the Butterfly as a base platform, often with few or no additional parts: * There's an award-winning educational robot based around the Butterfly called the ''FlutterBot''. * Project ''ButtLoad'' offers free plans to convert the Butterfly into a portable AVR-ISP for programming other AVR devices. * Several plans are available on the web to convert a Butterfly into an MP3 player. * ''C Programming for Microcontrollers'', a book for learning to program AVRs using C, was written for the Butterfly as development platform. * The Butterfly Logger is an open source

data logger A data logger (also datalogger or data recorder) is an electronic device that records data over time or about location either with a built-in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they a ...

based on the AVR Butterfly. * The Butteruino project is a set of libraries to integrate the AVR Butterfly with the Arduino development environment.

References

{{reflist

External links

Atmel's product page

Getting Started Guide

Atmel AVR Butterfly Mini-FAQ for Linux
Robotics hardware Atmel microcontrollers Educational hardware Single-board computers