Raspberry Pi

The Raspberry Pi is a credit card sized single board computer, which was developed by the British Raspberry Pi Foundation.

The compared to conventional personal computers very simply constructed and affordable with 25 or U.S. $ 35 calculator was developed by the Foundation with the aim to help young people develop programming and hardware skills. The board contains an on -chip system with a Broadcom 700 MHz ARM11 processor and depending on the model 256 or 512 MB ​​of RAM. The model B has an additional Ethernet interface and a second USB port. The operating system is customized versions of Linux, Android or other operating systems can be installed which support the ARM architecture. A separate hard drive interface does not exist, can instead SD memory cards are used as a boot medium.

By March 2014 more than 2.5 million units have been sold. The developers of the Raspberry Pi has received several innovation awards. There is a large range of accessories and software portfolio for a variety of applications. A common application is as a media center, because the computer video with full HD (1080p) resolution process and can output via the standard HDMI interface.

• 4.1 processor
• 4.2 graphics
• 4.3 GPIO
• 4.4 CSI

Background

Idea

The motive behind the development of an inexpensive computer was the declining number of computer science students at the University of Cambridge, and their deteriorating prior knowledge of programming. For one of the reasons we held that computers today are generally expensive and complex and therefore parents often forbid their children to experiment with the family PC. We therefore wanted to give young people a cheap computer for experimentation and learning of programming at hand. It was hoped that they would learn how in the early days of home computers (eg IMSAI 8080, Apple I, Sinclair ZX80 ) Computer Fundamentals and Programming playful.

Naming and logo

The name is pronounced like raspberry pie, the English word for raspberry cake. The " P " stands for " Python Interpreter", originally the computer should be supplied with built- interpreter for the Python programming language, similar to the home computers of the eighties almost always a BASIC interpreter was installed. The " Raspberry " builds on the tradition to name your computer after fruits, such as Apple or Acorn.

The logo of the project was selected through a public tender exercise. It shows a stylized raspberry, whose shape is derived from a geodesic dome.

Organization

The Raspberry Pi Foundation is a foundation and registered in England as a charity. It has set itself the goal to promote the study of computer science and related topics, especially at school. It was founded on May 5, 2009 in Caldecote, South Cambridgeshire, UK. The Trustees of the Foundation are:

• David Braben - Founder of computer games company Frontier Developments and co-author of the computer game Elite
• Jack Lang - former Acorn employee, angel investor and founder of several start-ups in the vicinity of Cambridge University
• Pete Lomas - founder and MD of the company Norcott Technologies
• Robert Mullins - University of Cambridge Computer Laboratory and St John 's College, Cambridge
• Alan Mycroft - Professor in the area of ​​" computing in University " at the Cambridge Computer Laboratory
• Eben Upton - Engineer at Broadcom Europe, founder of several software start - ups, and former Director in the area of ​​computer science at St. John 's College, Cambridge

Development

A prototype with an Atmel ATmega644 microcontroller - was produced in 2006. The schematics of the board have been published.

The performance of the appliance not convinced the developers. Because of the then incipient boom of smartphones, however, suitable ARM processors came on the market. It was found with the BCM2835 for cheap processor with a relatively high performance and designed for this CPU a new multi-layer board. For the Atmel one was still sufficient to use a breadboard.

50 Alpha boards were delivered in August 2011. These boards were functionally identical to the later model B of the Raspberry Pi, but larger to accommodate measurement points for troubleshooting. The retail version has the size of a credit card. In this test boards has already been shown that the desktop environment LXDE work under Debian as well as Quake 3 and H.264 video with a resolution of 1080p via HDMI. Since autumn 2012, a slightly modified version 2 is being sold. She has two mounting holes and some pins are configured differently. Was about the same time because of the unexpectedly high sales figures, the production of China will be moved to Wales and the memory of the B- model are doubled to 512MB. In the meantime (as of March 2014) were 2.5 million units sold, which was produced over a million in Wales.

On 14 May 2013, a camera module for Raspberry Pi came into the trade. A variant without an infrared filter is under the name Pi -NOL available ( November 2013 ).

On April 7, 2014, the Raspberry Pi Foundation announced a Raspberry Pi in the size and appearance of a DDR2 SODIMM memory lock. The model is designed with the technical specifications of the Model B respectively, but without having their own IO ports.

Specifications

The specifications of the two variants A and B of the Raspberry Pi are:

Hardware

Processor

The processor uses the ARMv6 instruction set. Furthermore, the ARM instruction set extensions Thumb and Java bytecode supports ( Jazelle ). The memory is connected via a 64 -bit bus and is soldered directly as a package - on-package on the processor.

Since the Raspberry Pi Foundation feared a reduction in the life at overclocking the processor with was "Sticky ( means: non -resettable ) Bit " feature, which is irrevocably set when the processor is overclocked and thus signals a void the warranty. After extensive testing showed that overclocking up to 1 GHz negligible effect on the life, the possibility was created on September 19, 2012 with a driver update, to overclock both CPU and GPU and memory without warranty. The frequency and voltage is only increased in the operation when the power is required and the temperature of the chips is not higher than 85 ° C. The sticky bit is only set when it is overclocked more than recommended.

A strong underclocking up to 50 MHz and decreasing the voltage is also possible that the model A leads to a significantly reduced power consumption especially.

Graphic

The ARM11 processor is combined with Broadcom's "Video Core" Grafikkoprozessor. OpenGL ES 2.0 is supported, and movies in full HD resolution ( 1080p30 H.264 high-profile ) can be decoded and output through the HDMI jack and composite video RCA jack. On 24 August 2012 it was announced that licenses for the hardware accelerated decoding of VC1 and MPEG-2 encoded video can be purchased separately. The license is limited to the in the order specified with the serial number Raspberry Pi, so that a separate license is required for each of these microcomputer. The existing license for decoding of H.264 - encoded video allowed, according to the Raspberry Pi Foundation and the encoding of such videos. In March 2014 laid open Broadcom documentation and driver code for the BCM21553 SoC, which is also a freelance graphic driver can be created for the BCM2835 used. This was published after a 10,000 U.S. $ doped programming contest in March 2014 by a single programmer.

GPIO

The Raspberry Pi offers a freely programmable interface (also known as GPIO General Purpose Input / Output), what LEDs, sensors, displays and other devices can be controlled. There are six GPIO ports, generally only the connection P1 is used. The GPIO interface P1 consists of 26 pins, of which

• Providing two pins, a voltage of 5 volts, however, also can be used to supply the power Raspberry Pi,
• 2 pins provide a voltage of 3.3 volts,
• Pin 1 as ground serves,
• 4 pins, which could in the future get another assignment, are also currently being connected to ground,
• 17 pins are programmable, which can take some special functions: 5-pin can be used as a SPI interface,
• 2 pins have a 1.8 k-ohm pull- up resistor ( to 3.3 V) and can be used as an I ² C interface,
• 2 pins can be used as a UART interface.

The added Come in Revision 2 GPIO interface P6 allows you to reset or start, after it was shut down the Raspberry Pi. To control the GPIOs exist libraries for many programming languages. Also a control by a terminal or web interface is possible.

CSI

For direct connection of a camera is a CSI (Camera Serial Interface) available. The available since May 2013 with 5 MP camera is controlled by CSI. The focus is not changed and the camera module has no microphone. The camera takes photos with a maximum resolution of 2592 * 1944 videos in 640 * 480.720 p or 1080p at up to 30 frames per second. In bad light easily generated noise.

Since October 2013, the variant "PI -NOL " is available without built-in infrared filter.

Operating Systems

Several open - source operating systems are available for the Raspberry Pi. So the buyer can choose which he wants to install. The installation is done either by loading an image to the SD card, or since June 3, 2013, with the easy -to-use in-house development NOOBS that must be copied to the card. With Berry boat, there is an equally easy to install boot loader that allows multiple operating systems on one card installed at a time, since version 1.3, which is also possible with NOOBS.

Previously run alongside various Linux distributions also have a development version of RISC OS 5 and Plan 9 on the Raspberry Pi, The BSD variants, FreeBSD and NetBSD have been ported to the Raspberry Pi. Although Windows RT will run on ARM processors, it is probably not possible to apply this operating system on the Raspberry Pi, because Windows 8 requires at least one gigabyte of RAM, which the Raspberry Pi has not.

The recommended Linux distribution is based on Debian Raspbian. In addition, is also a compiled for ARM processors version of Arch Linux and a version of Fedora - offered - under the name Pidora. Similarly, there is Kali Linux, the new version of the security distribution Backtrack and Bodhi Linux for the Raspberry Pi OpenSUSE also offers executable images and with the openSUSE Build Service the opportunity to create their own software packages and thus based distributions to create your own openSUSE.

With based on the Media Center XBMC distributions like OpenELEC, Raspbmc or XBian can the Raspberry Pi use as a media center. XBMC can also be used with the TV remote control.

Furthermore ported the Android system on the Raspberry Pi. A running beta version is available for download.

Contrary to initial assumptions, the Linux distribution Ubuntu will not install on the Raspberry Pi, since Ubuntu only supports ARMv7 (Cortex family), the Raspberry Pi, however, the ARMv6 architecture ( ARM11 Family ) is used.

Software

Some programs have been adapted for the Raspberry Pi to benefit from the hardware accelerated graphics by the GPU. This includes in particular the XBMC Media Center. As part of the adaptation of XBMC on the Raspberry Pi, a standalone video player with GPU support under the name OMXPlayer was developed. Also the game Minecraft is available in a special free version with integrated programming. The libraries Qt and NGL have been ported to the Raspberry Pi under the name " QtonPi ".

Since November 2013, any private user of the Raspberry Pi receives a free copy of the software Mathematica.

Media Coverage

A prototype of the computer was presented to the press on May 6, 2011. Since the sale of the Raspberry Pi mainly technically oriented media regularly report on new projects with the Raspberry Pi Raspberry Pi was awarded the Innovation of the Year at the T3 Gadget Awards 2012. Eben Upton, one of the developers of the Raspberry Pi was in 2013 awarded the silver medal of the Royal Academy of Engineering.

In May 2012, the first edition of Community Magazine MagPi was published. The magazine draws on all topics related to the Raspberry Pi. Since June 2013, this is an English and since August 2013, the German -language magazine "Raspberry Pi Geek " from Medialinx publisher.

Purpose

Because of the low price and low power consumption of the Raspberry Pi arising away from the intended use as a school computer other ways, such as music streaming client, Apple Time Capsule, Smart TV, Media Center, thin client or server, as control board in a Quadrocopter, as a weather station, FM radio station or as a control unit for dedicated Bitcoin mining hardware.

Alternatives

After the great success of the Raspberry Pi single-board some similar came on the market. These are, in particular, the Cubieboard at a faster ARM CPU and more memory for $ 49 and based on the BeagleBoard BeagleBone Black by CircuitCo with a faster processor from Texas Instruments and a larger number of I / O interfaces for 45 U.S. dollar. The BeagleBone Black supports Android ( rowboat ), Ubuntu, openSUSE, and Angstrom, and several other operating systems such as FreeBSD, QNX, and Windows Embedded.

Further alternatives include:

• Arduino platform
• Ethernut
• PandaBoard
• TinkerForge
• Cubieboard
• OLinuXino: A10- A20 and OLinuXino - LIME - OLinuXino -MICRO
• Wallboard solo, dual, or quad ( Freescale i.MX 6 SoC Cortex- A9 based)
• NanoPC -T1

For the alternative systems, there are no comparable large core communities, but by the increasing Verfügbarbeit different standard operating systems expands at the same time the basis for further future software developments.