Raspberry Pi

"RPi" redirects here. For other uses, see RPI.

Raspberry Pi logo

Raspberry Pi 1

Raspberry Pi 1 model B+
Release date	February 2012 (2012-02)
Introductory price	US$25 (model A, B+), US$20 (model A+), US$35 (RPi 1 model B, RPi 2 model B), US$30 (CM)
Operating system	Linux (e.g. Raspbian), RISC OS, FreeBSD, NetBSD, Plan 9, Inferno, AROS
CPU	700 MHz single-core ARM1176JZF-S (model A, A+, B, B+, CM)
Memory	256 MB (model A, A+, B rev 1) 512 MB (model B rev 2, B+, CM)
Storage	SDHC slot (model A and B), MicroSDHC slot (model A+ and B+), 4 GB eMMC IC chip (model CM)
Graphics	Broadcom VideoCore IV
Power	1.5 W (model A), 1.0 W (model A+), 3.5 W (model B) or 3.0 W (model B+)

Raspberry Pi 2

Raspberry Pi 2 model B
Release date	February 2015 (2015-02)
Introductory price	US$35
Operating system	Same as for Raspberry Pi 1 plus Windows 10 IoT Core and additional distributions of Linux such as Ubuntu
CPU	900 MHz quad-core ARM Cortex-A7
Memory	1 GB RAM
Storage	MicroSDHC slot
Graphics	Broadcom VideoCore IV
Power	4.0 W

The Raspberry Pi is a series of credit card–sized single-board computers developed in the UK by the Raspberry Pi Foundation with the intention of promoting the teaching of basic computer science in schools and third world countries.

The original Raspberry Pi and Raspberry Pi 2 are manufactured in several board configurations through licensed manufacturing agreements with Newark element14 (Premier Farnell), RS Components and Egoman. These companies sell the Raspberry Pi online. Egoman produces a version for distribution solely in Taiwan, which can be distinguished from other Pis by their red colouring and lack of FCC/CE marks. The hardware is the same across all manufacturers.

The original Raspberry Pi is based on the Broadcom BCM2835 system on a chip (SoC), which includes an ARM1176JZF-S 700 MHz processor, VideoCore IV GPU, and was originally shipped with 256 megabytes of RAM, later upgraded (models B and B+) to 512 MB. The system has Secure Digital (SD) (models A and B) or MicroSD (models A+ and B+) sockets for boot media and persistent storage.

In 2014, the Raspberry Pi Foundation launched the Compute Module, which packages a BCM2835 with 512 MB RAM and an eMMC flash chip into a module for use as a part of embedded systems.

The Foundation provides Debian and Arch Linux ARM distributions for download. Tools are available for Python as the main programming language, with support for BBC BASIC (via the RISC OS image or the Brandy Basic clone for Linux), C, C++, Java, Perl and Ruby.

As of 8 June 2015, about five to six million Raspberry Pis have been sold. While already the fastest selling British personal computer, it has also shipped the second largest number of units behind the Amstrad PCW, the "Personal Computer Word-processor", which sold eight million.

In early February 2015, the next-generation Raspberry Pi, Raspberry Pi 2, was released. The new computer board is initially available only in one configuration (model B) and features a Broadcom BCM2836 SoC, with a quad-core ARM Cortex-A7 CPU and a VideoCore IV dual-core GPU; 1 GB of RAM with remaining specifications being similar to those of the previous generation model B+. The Raspberry Pi 2 retains the same US$35 price point of the model B, with the US$20 model A+ remaining on sale.

Hardware

The Raspberry Pi hardware has evolved through several versions that feature variations in hardware performance, memory capacity, and peripheral device support.

This block diagram depicts models A, B, A+, and B+. Model A and A+ lack the Ethernet and USB hub components. The Ethernet adapter is connected to an additional USB port. In model A and A+ the USB port is connected directly to the SoC. On model B+ the chip contains a five-point USB hub, of which four ports are available, while model B only provides two.

Processor

The SoC used in the first generation Raspberry Pi is somewhat equivalent to the chip used in older smartphones (such as iPhone / 3G / 3GS). The Raspberry Pi is based on the Broadcom BCM2835 system on a chip (SoC), which includes an 700 MHz ARM1176JZF-S processor, VideoCore IV GPU, and RAM. It has a Level 1 cache of 16 KB and a Level 2 cache of 128 KB. The Level 2 cache is used primarily by the GPU. The SoC is stacked underneath the RAM chip, so only its edge is visible.

Performance of first generation models

While operating at 700 MHz by default, the first generation Raspberry Pi provided a real world performance roughly equivalent to 0.041 GFLOPS. On the CPU level the performance is similar to a 300 MHz Pentium II of 1997-1999. The GPU provides 1 Gpixel/s or 1.5 Gtexel/s of graphics processing or 24 GFLOPS of general purpose computing performance. The graphics capabilities of the Raspberry Pi are roughly equivalent to the level of performance of the Xbox of 2001.

The LINPACK single node compute benchmark results in a mean single precision performance of 0.065 GFLOPS and a mean double precision performance of 0.041 GFLOPS for one Raspberry Pi Model-B board. A cluster of 64 Raspberry Pi Model-B computers, labeled "Iridis-pi", achieved a LINPACK HPL suite result of 1.14 GFLOPS (n=10240) at 216 watts for c. US$4,000.

Raspberry Pi 2 is based on Broadcom BCM2836 SoC, which includes a quad-core Cortex-A7 CPU running at 900 MHz and 1 GB RAM. It is described as 4–6 times more powerful than its predecessor. The GPU is identical.

Overclocking

The first generation Raspberry Pi chip operated at 700 MHz by default and did not become hot enough to need a heat sink or special cooling, unless the chip was overclocked. The second generation runs at 900 MHz by default, and also does not become hot enough to need a heatsink or special cooling. Again overclocking may heat up the SoC more than usual.

Most Raspberry Pi chips could be overclocked to 800 MHz and some even higher to 1000 MHz. There are reports the second generation can be similarly overclocked, in extreme cases, even to 1500 MHz (discarding all safety features and over voltage limitations). In the Raspbian Linux distro the overclocking options on boot can be done by a software command running "sudo raspi-config" without voiding the warranty. In those cases the Pi automatically shuts the overclocking down in case the chip reaches 85 °C (185 °F), but it is possible to overrule automatic over voltage and overclocking settings (voiding the warranty). In that case, one can try putting an appropriately sized heatsink on it to keep the chip from heating up far above 85 °C.

Newer versions of the firmware contain the option to choose between five overclock ("turbo") presets that when turned on try to get the most performance out of the SoC without impairing the lifetime of the Pi. This is done by monitoring the core temperature of the chip, and the CPU load, and dynamically adjusting clock speeds and the core voltage. When the demand is low on the CPU, or it is running too hot, the performance is throttled, but if the CPU has much to do, and the chip's temperature is acceptable, performance is temporarily increased, with clock speeds of up to 1 GHz, depending on the individual board, and on which of the turbo settings is used. The five settings are:

• none; 700 MHz ARM, 250 MHz core, 400 MHz SDRAM, 0 overvolt,
• modest; 800 MHz ARM, 250 MHz core, 400 MHz SDRAM, 0 overvolt,
• medium; 900 MHz ARM, 250 MHz core, 450 MHz SDRAM, 2 overvolt,
• high; 950 MHz ARM, 250 MHz core, 450 MHz SDRAM, 6 overvolt,
• turbo; 1000 MHz ARM, 500 MHz core, 600 MHz SDRAM, 6 overvolt.

In the highest (turbo) preset the SDRAM clock was originally 500 MHz, but this was later changed to 600 MHz because 500 MHz sometimes causes SD card corruption. Simultaneously in high mode the core clock speed was lowered from 450 to 250 MHz, and in medium mode from 333 to 250 MHz.

RAM

On the older beta model B boards, 128 MB was allocated by default to the GPU, leaving 128 MB for the CPU. On the first 256 MB release model B (and model A), three different splits were possible. The default split was 192 MB (RAM for CPU), which should be sufficient for standalone 1080p video decoding, or for simple 3D, but probably not for both together. 224 MB was for Linux only, with just a 1080p framebuffer, and was likely to fail for any video or 3D. 128 MB was for heavy 3D, possibly also with video decoding (e.g. XBMC). Comparatively the Nokia 701 uses 128 MB for the Broadcom VideoCore IV. For the new model B with 512 MB RAM initially there were new standard memory split files released( arm256_start.elf, arm384_start.elf, arm496_start.elf) for 256 MB, 384 MB and 496 MB CPU RAM (and 256 MB, 128 MB and 16 MB video RAM). But a week or so later the RPF released a new version of start.elf that could read a new entry in config.txt (gpu_mem=xx) and could dynamically assign an amount of RAM (from 16 to 256 MB in 8 MB steps) to the GPU, so the older method of memory splits became obsolete, and a single start.elf worked the same for 256 and 512 MB Raspberry Pis.

The Raspberry Pi 2 has 1 GB of RAM.

Networking

Though the model A and A+ do not have an 8P8C ("RJ45") Ethernet port, they can be connected to a network using an external user-supplied USB Ethernet or Wi-Fi adapter. On the model B and B+ the Ethernet port is provided by a built-in USB Ethernet adapter.

Peripherals

The Raspberry Pi may be operated with any generic USB computer keyboard and mouse.

Video

The video controller is capable of standard modern TV resolutions, such as HD and Full HD, and higher or lower monitor resolutions and older standard CRT TV resolutions. As shipped (i.e. without custom overclocking) it is capable of the following: 640×350 EGA; 640×480 VGA; 800×600 SVGA; 1024×768 XGA; 1280×720 720p HDTV; 1280×768 WXGA variant; 1280×800 WXGA variant; 1280×1024 SXGA; 1366×768 WXGA variant; 1400×1050 SXGA+; 1600×1200 UXGA; 1680×1050 WXGA+; 1920×1080 1080p HDTV; 1920×1200 WUXGA. It can generate 576i and 480i composite video signals for PAL-BGHID, PAL-M, PAL-N, NTSC and NTSC-J.

Real-time clock

The Raspberry Pi does not come with a real-time clock, which means it cannot keep track of the time of day while it is not powered on.

As alternatives, a program running on the Pi can get the time from a network time server or user input at boot time.

A real-time clock (such as the DS1307) with battery backup can be added (often via the I²C interface).

Specifications

	Raspberry Pi 1 Model A	Raspberry Pi 1 Model A+	Raspberry Pi 1 Model B	Raspberry Pi 1 Model B+	Raspberry Pi 2 Model B	Compute Module (Note: all interfaces are via 200-pin DDR2 SO-DIMM connector.)
Release Date:	February 2012	November 2014	N/A	July 2014	February 2015	N/A
Target price:	US$25	US$20	US$35	US$25	US$35	US$30 (in batches of 100)
SoC:	Broadcom BCM2835 (CPU, GPU, DSP, SDRAM, one USB port)				Broadcom BCM2836 (CPU, GPU, DSP, SDRAM, one USB port)	Broadcom BCM2835 (CPU, GPU, DSP, SDRAM, one USB port)
CPU:	700 MHz single-core ARM1176JZF-S				900 MHz quad-core ARM Cortex-A7	700 MHz single-core ARM1176JZF-S
GPU:	Broadcom VideoCore IV @ 250 MHz OpenGL ES 2.0 (24 GFLOPS) MPEG-2 and VC-1 (with license), 1080p30 H.264/MPEG-4 AVC high-profile decoder and encoder
Memory (SDRAM):	256 MB (shared with GPU)		512 MB (shared with GPU) as of 15 October 2012		1 GB (shared with GPU)	512 MB (shared with GPU)
USB 2.0 ports:	1 (direct from BCM2835 chip)		2 (via the on-board 3-port USB hub)	4 (via the on-board 5-port USB hub)		1 (direct from BCM2835 chip)
Video input:	15-pin MIPI camera interface (CSI) connector, used with the Raspberry Pi camera or Raspberry Pi NoIR camera					2× MIPI camera interface (CSI)
Video outputs:	HDMI (rev 1.3 & 1.4), 14 HDMI resolutions from 640×350 to 1920×1200 plus various PAL and NTSC standards, composite video (PAL and NTSC) via RCA jack	HDMI (rev 1.3 & 1.4), 14 HDMI resolutions from 640×350 to 1920×1200 plus various PAL and NTSC standards, composite video (PAL and NTSC) via 3.5 mm TRRS jack shared with audio out	HDMI (rev 1.3 & 1.4), 14 HDMI resolutions from 640×350 to 1920×1200 plus various PAL and NTSC standards, composite video (PAL and NTSC) via RCA jack	HDMI (rev 1.3 & 1.4), 14 HDMI resolutions from 640×350 to 1920×1200 plus various PAL and NTSC standards, composite video (PAL and NTSC) via 3.5 mm TRRS jack shared with audio out		HDMI, 2× MIPI display interface (DSI), MIPI display interface (DSI) for raw LCD panels, composite video
Audio inputs:	As of revision 2 boards, I²S
Audio outputs:	Analog via 3.5 mm phone jack; digital via HDMI and, as of revision 2 boards, I²S					Analog, HDMI, I²S
On-board storage:	SD / MMC / SDIO card slot (3.3 V with card power only)	MicroSD slot	SD / MMC / SDIO card slot	MicroSD slot		4 GB eMMC flash memory chip; may or may not support external SD cards with configuration changes
On-board network:	None		10/100 Mbit/s Ethernet (8P8C) USB adapter on the third/fifth port of the USB hub (SMSC lan9514-jzx)			None
Low-level peripherals:	8× GPIO plus the following, which can also be used as GPIO: UART, I²C bus, SPI bus with two chip selects, I²S audio +3.3 V, +5 V, ground	17× GPIO plus the same specific functions, and HAT ID bus	8× GPIO plus the following, which can also be used as GPIO: UART, I²C bus, SPI bus with two chip selects, I²S audio +3.3 V, +5 V, ground. An additional 4× GPIO are available on the P5 pad if the user is willing to make solder connections	17× GPIO plus the same specific functions, and HAT ID bus		46× GPIO, some of which can be used for specific functions including I²C, SPI, UART, PCM, PWM
Power ratings:	300 mA (1.5 W)	200 mA (1 W)	700 mA (3.5 W)	600 mA (3.0 W)	800 mA (4.0 W)	similar to Model A+
Power source:	5 V via MicroUSB or GPIO header					5 V
Size:	85.60 mm × 56.5 mm (3.370 in × 2.224 in) – not including protruding connectors	65 mm × 56.5 mm (2.56 in × 2.22 in) – (same as HAT board) and 10 mm high	85.60 mm × 56.5 mm (3.370 in × 2.224 in) – not including protruding connectors			67.6 mm × 30 mm (2.66 in × 1.18 in)
Weight:	45 g (1.6 oz)	23 g (0.81 oz)	45 g (1.6 oz)			7 g (0.25 oz)
	Model A	Model A+	Model B	Model B+	Generation 2 Model B	Compute Module

Connectors

• 
  Location of connectors and main ICs on Raspberry Pi 1 model A+ revision 1.1
• 
  Location of connectors and main ICs on Raspberry Pi 1 model B revision 2
• 
  Location of connectors and main ICs on Raspberry Pi 1 model B+ revision 1.2, and Raspberry Pi 2 model B

GPIO connector

RPi A+, B+ and 2B GPIO J8 40-pin pinout. Models A and B have only the first 26 pins.

GPIO#	2nd func	pin#		pin#	2nd func	GPIO#
N/A	+3V3	1		2	+5V	N/A
GPIO2	SDA1 (I2C)	3		4	+5V	N/A
GPIO3	SCL1 (I2C)	5		6	GND	N/A
GPIO4	GCLK	7		8	TXD0 (UART)	GPIO14
N/A	GND	9		10	RXD0 (UART)	GPIO15
GPIO17	GEN0	11		12	GEN1	GPIO18
GPIO27	GEN2	13		14	GND	N/A
GPIO22	GEN3	15		16	GEN4	GPIO23
N/A	+3V3	17		18	GEN5	GPIO24
GPIO10	MOSI (SPI)	19		20	GND	N/A
GPIO9	MISO (SPI)	21		22	GEN6	GPIO25
GPIO11	SCLK (SPI)	23		24	CE0_N (SPI)	GPIO8
N/A	GND	25		26	CE1_N (SPI)	GPIO7
(Models A and B stop here)
EEPROM	ID_SD	27		28	ID_SC	EEPROM
GPIO5	N/A	29		30	GND	N/A
GPIO6	N/A	31		32	-	GPIO12
GPIO13	N/A	33		34	GND	N/A
GPIO19	N/A	35		36	N/A	GPIO16
GPIO26	N/A	37		38	Digital IN	GPIO20
N/A	GND	39		40	Digital OUT	GPIO21

Model B rev 2 also has a pad (called P5 on the board and P6 on the schematics) of 8 pins offering access to an additional 4 GPIO connections.

Function	2nd func	pin#		pin#	2nd func	Function
N/A	+5V	1		2	+3V3	N/A
GPIO28	GPIO_GEN7	3		4	GPIO_GEN8	GPIO29
GPIO30	GPIO_GEN9	5		6	GPIO_GEN10	GPIO31
N/A	GND	7		8	GND	N/A

Models A and B provide GPIO access to the ACT status LED using GPIO 16. Models A+ and B+ provide GPIO access to the ACT status LED using GPIO 47, and the power status LED using GPIO 35.

Accessories

• Camera – On 14 May 2013, the foundation and the distributors RS Components & Premier Farnell/Element 14 launched the Raspberry Pi camera board with a firmware update to accommodate it. The camera board is shipped with a flexible flat cable that plugs into the CSI connector located between the Ethernet and HDMI ports. In Raspbian, one enables the system to use the camera board by the installing or upgrading to the latest version of the operating system (OS) and then running Raspi-config and selecting the camera option. The cost of the camera module is €20 in Europe (9 September 2013). It can produce 1080p, 720p and 640x480p video. The footprint dimensions are 25 mm x 20 mm x 9 mm.
• Gertboard – A Raspberry Pi Foundation sanctioned device, designed for educational purposes, that expands the Raspberry Pi's GPIO pins to allow interface with and control of LEDs, switches, analog signals, sensors and other devices. It also includes an optional Arduino compatible controller to interface with the Pi.
• Infrared Camera – In October 2013, the foundation announced that they would begin producing a camera module without an infrared filter, called the Pi NoIR.
• HAT (Hardware Attached on Top) expansion boards – Together with the model B+, inspired by the Arduino shield boards, the interface for HAT boards was devised by the Raspberry Pi Foundation. Each HAT board carries a small EEPROM (typically a CAT24C32WI-GT3) containing the relevant details of the board, so that the Raspberry Pi's OS is informed of the HAT, and the technical details of it, relevant to the OS using the HAT. Mechanical details of a HAT board, that use the four mounting holes in their rectangular formation.

Software

Operating systems

The Raspberry Pi primarily uses Linux-kernel-based operating systems.

The ARM11 chip at the heart of the Pi (first generation models) is based on version 6 of the ARM. The current releases of several popular versions of Linux, including Ubuntu, will not run on the ARM11. It is not possible to run Windows on the original Raspberry Pi, though the new Raspberry Pi 2 can also run on Windows 10 IoT Core operating system. The Raspberry Pi 2 currently only supports Ubuntu Snappy Core, Raspbian, OpenELEC and RISC OS.

The install manager for the Raspberry Pi is NOOBS. The operating systems included with NOOBS are:

• Arch Linux ARM
• OpenELEC
• Pidora (Fedora Remix)
• Puppy Linux
• Raspbmc and the XBMC open source digital media center
• RISC OS – is the operating system of the first ARM-based computer.
• Raspbian (recommended for Raspberry Pi 1) – Maintained independently of the Foundation; based on the Debian ARM hard-float (armhf) architecture port originally designed for ARMv7 and later processors (with Jazelle RCT/ThumbEE, VFPv3, and NEON SIMD extensions), compiled for the more limited ARMv6 instruction set of the Raspberry Pi 1. A minimum size of 4 GB SD card is required for the Raspbian images provided by the Raspberry Pi Foundation. There is a Pi Store for exchanging programs.
  • The Raspbian Server Edition is a stripped version with fewer software packages bundled as compared to the usual desktop computer oriented Raspbian.
  • The Wayland display server protocol enable the efficient use of the GPU for hardware accelerated GUI drawing functions. on 16 April 2014 a GUI shell for Weston called Maynard was released.
  • PiBang Linux is derived from Raspbian.
  • Raspbian for Robots – is a fork of Raspbian for robotics projects with LEGO, Grove, and Arduino.

Other operating systems

• Xbian – Using the Kodi (formerly XBMC) open source digital media center
• openSUSE
• Raspberry Pi Fedora Remix
• Slackware ARM – Version 13.37 and later runs on the Raspberry Pi without modification. The 128–496 MB of available memory on the Raspberry Pi is at least twice the minimum requirement of 64 MB needed to run Slackware Linux on an ARM or i386 system. (Whereas the majority of Linux systems boot into a graphical user interface, Slackware's default user environment is the textual shell / command line interface.) The Fluxbox window manager running under the X Window System requires an additional 48 MB of RAM.
• FreeBSD and NetBSD are general operating systems.
• Plan 9 from Bell Labs and Inferno (in beta)
• Moebius – A light ARM HF distribution based on Debian. It uses Raspbian repository, but it fits in a 128 MB SD card. It has just minimal services and its memory usage is optimized to keep a small footprint.
• OpenWrt – is primarily used on embedded devices to route network traffic.
• Kali Linux – is a Debian-derived distro designed for digital forensics and penetration testing.
• Pardus ARM – is a Debian-Based operating system which is the light version of the Pardus (operating system).
• Instant WebKiosk – is an operating system for digital signage purposes (web and media views).
• Ark OS – is designed for website and email self-hosting.
• Minepion – is a dedicated operating system for mining cryptocurrency.
• Kano OS
• Nard SDK for industrial embedded systems
• Sailfish OS with Raspberry Pi 2 (due to use ARM Cortex-A7 CPU; Raspberry Pi 1 uses different ARMv6 architecture and Sailfish requires ARMv7.)
• Tiny Core Linux – a minimal Linux operating system focused on providing a base system using BusyBox and FLTK. Designed to run primarily in RAM.
• "Windows 10 IoT Core" – Microsoft offers a free edition of Windows 10, known as Windows 10 IoT Core, that runs natively on the Raspberry Pi 2.
• IPFire – a dedicated firewall/router distribution for the protection of a SOHO LAN; runs only on a Raspberry Pi 1; porting to the Raspberry Pi 2 is not planned for now.
• xv6 – a modern reimplementation of Sixth Edition Unix OS for teaching purposes; it is ported to Raspberry Pi from MIT xv6; this xv6 port can boot from NOOBS.

Planned operating systems

• Haiku – This open source BeOS clone has been targeted for the Raspberry Pi and several other ARM boards. Work began in 2011, on the model 1 but only the model 2 will be supported.

Driver APIs

Scheme of the implemented APIs: OpenMAX, OpenGL ES and OpenVG

Raspberry Pi can use a VideoCore IV GPU via a binary blob, which is loaded into the GPU at boot time from the SD-card, and additional software, that initially was closed source. This part of the driver code was later released, however much of the actual driver work is done using the closed source GPU code. Application software use calls to closed source run-time libraries (OpenMax, OpenGL ES or OpenVG) which in turn calls an open source driver inside the Linux kernel, which then calls the closed source VideoCore IV GPU driver code. The API of the kernel driver is specific for these closed libraries. Video applications use OpenMAX, 3D applications use OpenGL ES and 2D applications use OpenVG which both in turn use EGL. OpenMAX and EGL use the open source kernel driver in turn.

Third party application software

• AstroPrint – Since August 2014, AstroPrint's Wireless 3D Printing software can be run on the Pi 2
• Mathematica – Since 21 November 2013, Raspbian includes a full installation of this proprietary software for free. As of 24 August 2015, the version is Mathematica 10.2.
• Minecraft – Released 11 February 2013, a version for the Raspberry Pi, in which you can modify the game world with code.
• UserGate Web Filter – On 20 September 2013, Florida-based security vendor Entensys announced porting UserGate Web Filter to Raspberry Pi platform.
• Julia – Since May 2015, Julia programming language compiles and runs on the Pi 2, and the original, in an alpha state.

Tracking Raspberry Pi online on a global map

Ryan Walmsley, a UK school student created a site in 2012, to register and track any Raspberry Pi across the globe. It became very popular soon after its launch. The current site is powered by Google Maps and Digital Ocean and is free. It has a limitation of registering only one Raspberry Pi per unique email id. It uses IP based basic location tracking and is fairly accurate up to Locale or City level.

Reception and use

Technology writer Glyn Moody described the project in May 2011 as a "potential BBC Micro 2.0", not by replacing PC compatible machines but by supplementing them. In March 2012 Stephen Pritchard echoed the BBC Micro successor sentiment in ITPRO. Alex Hope, co-author of the Next Gen report, is hopeful that the computer will engage children with the excitement of programming. Co-author Ian Livingstone suggested that the BBC could be involved in building support for the device, possibly branding it as the BBC Nano. Chris Williams, writing in The Register sees the inclusion of programming languages such as Kids Ruby, Scratch and BASIC as a "good start" to equip kids with the skills needed in the future – although it remains to be seen how effective their use will be. The Centre for Computing History strongly supports the Raspberry Pi project, feeling that it could "usher in a new era". Before release, the board was showcased by ARM's CEO Warren East at an event in Cambridge outlining Google's ideas to improve UK science and technology education.

Harry Fairhead, however, suggests that more emphasis should be put on improving the educational software available on existing hardware, using tools such as Google App Inventor to return programming to schools, rather than adding new hardware choices. Simon Rockman, writing in a ZDNet blog, was of the opinion that teens will have "better things to do", despite what happened in the 1980s.

In October 2012, the Raspberry Pi won T3's Innovation of the Year award, and futurist Mark Pesce cited a (borrowed) Raspberry Pi as the inspiration for his ambient device project MooresCloud. In October 2012, the British Computer Society reacted to the announcement of enhanced specifications by stating, "it's definitely something we'll want to sink our teeth into."

In February 2015, a switched-mode power supply chip, designated U16, of the Raspberry Pi 2 model B version 1.1 (the initially released version) was found to be vulnerable to flashes of light, particularly the light from xenon camera flashes and green and red laser pointers. However, other bright lights, particularly ones that are on continuously, were found to have no effect. The symptom was the Raspberry Pi 2 spontaneously rebooting or turning off when these lights were flashed at the chip. Initially, some users and commenters suspected that the electromagnetic pulse from the xenon flash tube was causing the problem by interfering with the computer's digital circuitry, but this was ruled out by tests where the light was either blocked by a card or aimed at the other side of the Raspberry Pi 2, both of which did not cause a problem. The problem was narrowed down to the U16 chip by covering first the system on a chip (main processor) and then U16 with opaque poster mounting compound. Light being the sole culprit, instead of EMP, was further confirmed by the laser pointer tests, where it was also found that less opaque covering was needed to shield against the laser pointers than to shield against the xenon flashes. The U16 chip seems to be bare silicon without a plastic cover (i.e. a chip-scale package or wafer-level package), which would, if present, block the light. Based on the facts that the chip, like all semiconductors, is light-sensitive (photovoltaic effect), that silicon is transparent to infrared light, and that xenon flashes emit more infrared light than laser pointers (therefore requiring more light shielding), it is currently thought that this combination of factors allows the sudden bright infrared light to cause an instability in the output voltage of the power supply, triggering shutdown or restart of the Raspberry Pi 2. Unofficial workarounds include covering U16 with opaque material (such as electrical tape, lacquer, poster mounting compound, or even balled-up bread), putting the Raspberry Pi 2 in a case, and avoiding taking photos of the top side of the board with a xenon flash. This issue was not caught before the release of the Raspberry Pi 2 because while commercial electronic devices are routinely subjected to tests of susceptibility to radio interference, it is not standard or common practice to test their susceptibility to optical interference.

Community

The Raspberry Pi community was described by Jamie Ayre of FLOSS software company AdaCore as one of the most exciting parts of the project. Community blogger Russell Davis said that the community strength allows the Foundation to concentrate on documentation and teaching. The community developed a fanzine around the platform called The MagPi which in 2015, was handed over to the Raspberry Pi Foundation by its volunteers to be continued in-house. A series of community Raspberry Jam events have been held across the UK and around the world.

Use in education

As of January 2012, enquiries about the board in the United Kingdom have been received from schools in both the state and private sectors, with around five times as much interest from the latter. It is hoped that businesses will sponsor purchases for less advantaged schools. The CEO of Premier Farnell said that the government of a country in the Middle East has expressed interest in providing a board to every schoolgirl, in order to enhance her employment prospects.

In 2014, the Raspberry Pi Foundation hired a number of its community members including ex-teachers and software developers to launch a set of free learning resources for its website. The resources are freely licensed under Creative Commons, and contributions and collaborations are encouraged on social coding platform GitHub.

The Foundation also started a teacher training course called Picademy with the aim of helping teachers prepare for teaching the new computing curriculum using the Raspberry Pi in the classroom. The continued professional development course is provided free for teachers and is run by the Foundation's education team.

Reviews

Raspberry Pi model B rev. 1 was rated 4/5 by PCMag, while Raspberry Pi model B rev. 2 was rated 4.1/5 by Board-DB.org.

History

An early alpha-test board in operation using different layout from later beta and production boards

In 2006, early concepts of the Raspberry Pi were based on the Atmel ATmega644 microcontroller. Its schematics and PCB layout are publicly available. Foundation trustee Eben Upton assembled a group of teachers, academics and computer enthusiasts to devise a computer to inspire children. The computer is inspired by Acorn's BBC Micro of 1981. Pi's model A, model B and model B+ are references to the original models of the British educational BBC Micro computer, developed by Acorn Computers. The first ARM prototype version of the computer was mounted in a package the same size as a USB memory stick. It had a USB port on one end and an HDMI port on the other.

The Foundation's goal was to offer two versions, priced at US$25 and US$35. They started accepting orders for the higher priced model B on 29 February 2012, the lower cost model A on 4 February 2013. and the even lower cost (US$20) A+ on 10 November 2014.

Pre-launch

• July 2011 (2011-07): Trustee Eben Upton publicly approached the RISC OS Open community in July 2011 to enquire about assistance with a port. Adrian Lees at Broadcom has since worked on the port, with his work being cited in a discussion regarding the graphics drivers. This port is now included in NOOBS.
• August 2011 – 50 alpha boards are manufactured. These boards were functionally identical to the planned model B, but they were physically larger to accommodate debug headers. Demonstrations of the board showed it running the LXDE desktop on Debian, Quake 3 at 1080p, and Full HD MPEG-4 video over HDMI.
• October 2011 – A version of RISC OS 5 was demonstrated in public, and following a year of development the port was released for general consumption in November 2012.
• December 2011 – Twenty-five model B Beta boards were assembled and tested from one hundred unpopulated PCBs. The component layout of the Beta boards was the same as on production boards. A single error was discovered in the board design where some pins on the CPU were not held high; it was fixed for the first production run. The Beta boards were demonstrated booting Linux, playing a 1080p movie trailer and the Rightware Samurai OpenGL ES benchmark.
• Early 2012 – During the first week of the year, the first 10 boards were put up for auction on eBay. One was bought anonymously and donated to the museum at The Centre for Computing History in Suffolk, England. The ten boards (with a total retail price of £220) together raised over £16,000, with the last to be auctioned, serial number No. 01, raising £3,500. In advance of the anticipated launch at the end of February 2012, the Foundation's servers struggled to cope with the load placed by watchers repeatedly refreshing their browsers.

Launch

Raspberry Pi model A

• 19 February 2012 – The first proof of concept SD card image that could be loaded onto an SD card to produce a preliminary operating system is released. The image was based on Debian 6.0 (Squeeze), with the LXDE desktop and the Midori browser, plus various programming tools. The image also runs on QEMU allowing the Raspberry Pi to be emulated on various other platforms.
• 29 February 2012 – Initial sales commence 29 February 2012 at 06:00 UTC;. At the same time, it was announced that the model A, originally to have had 128 MB of RAM, was to be upgraded to 256 MB before release. The Foundation's website also announced: "Six years after the project's inception, we're nearly at the end of our first run of development – although it's just the beginning of the Raspberry Pi story." The web-shops of the two licensed manufacturers selling Raspberry Pi's within the United Kingdom, Premier Farnell and RS Components, had their websites stalled by heavy web traffic immediately after the launch (RS Components briefly going down completely). Unconfirmed reports suggested that there were over two million expressions of interest or pre-orders. The official Raspberry Pi Twitter account reported that Premier Farnell sold out within a few minutes of the initial launch, while RS Components took over 100,000 pre orders on day one. Manufacturers were reported in March 2012 to be taking a "healthy number" of pre-orders.
• March 2012 – Shipping delays for the first batch were announced in March 2012, as the result of installation of an incorrect Ethernet port, but the Foundation expected that manufacturing quantities of future batches could be increased with little difficulty if required. "We have ensured we can get them [the Ethernet connectors with magnetics] in large numbers and Premier Farnell and RS Components [the two distributors] have been fantastic at helping to source components," Upton said. The first batch of 10,000 boards was manufactured in Taiwan and China.
• 8 March 2012 – Release Raspberry Pi Fedora Remix, the recommended Linux distribution, developed at Seneca College in Canada.
• March 2012 – The Debian port is initiated by Mike Thompson, former CTO of Atomz. The effort was largely carried out by Thompson and Peter Green, a volunteer Debian developer, with some support from the Foundation, who tested the resulting binaries that the two produced during the early stages (neither Thompson nor Green had physical access to the hardware, as boards were not widely accessible at the time due to demand). While the preliminary proof of concept image distributed by the Foundation before launch was also Debian-based, it differed from Thompson and Green's Raspbian effort in a couple of ways. The POC image was based on then-stable Debian Squeeze, while Raspbian aimed to track then-upcoming Debian Wheezy packages. Aside from the updated packages that would come with the new release, Wheezy was also set to introduce the armhf architecture, which became the raison d'être for the Raspbian effort. The Squeeze-based POC image was limited to the armel architecture, which was, at the time of Squeeze's release, the latest attempt by the Debian project to have Debian run on the newest ARM EABI. The armhf architecture in Wheezy intended to make Debian run on the ARM VFP hardware floating-point unit, while armel was limited to emulating floating point operations in software. Since the Raspberry Pi included a VFP, being able to make use of the hardware unit would result in performance gains and reduced power usage for floating point operations. The armhf effort in mainline Debian, however, was orthogonal to the work surrounding the Pi and only intended to allow Debian to run on ARMv7 at a minimum, which would mean the Pi, an ARMv6 device, would not benefit. As a result, Thompson and Green set out to build the 19,000 Debian packages for the device using a custom build cluster.

Post-launch

• 16 April 2012 – Reports appear from the first buyers who had received their Raspberry Pi.
• 20 April 2012 – The schematics for the model A and model B are released.
• 18 May 2012 – The Foundation reported on its blog about a prototype camera module they had tested. The prototype used a 14-megapixel module.
• 22 May 2012 – Over 20,000 units had been shipped.
• 16 July 2012 – It was announced that 4,000 units were being manufactured per day, allowing Raspberry Pis to be bought in bulk.
• 24 August 2012 – Hardware accelerated video (H.264) encoding becomes available after it became known that the existing license also covered encoding. Previously it was thought that encoding would be added with the release of the announced camera module. However, no stable software exists for hardware H.264 encoding. At the same time the Foundation released two additional codecs that can be bought separately, MPEG-2 and Microsoft's VC-1. Also it was announced that the Pi will implement CEC, enabling it to be controlled with the television's remote control.
• July 2012 – Release of Raspbian.
• 5 September 2012 – The Foundation announced a second revision of the Raspberry Pi Model B. A revision 2.0 board is announced, with a number of minor corrections and improvements.
• 6 September 2012 – Announcement that in future the bulk of Raspberry Pi units would be manufactured in the UK, at Sony's manufacturing facility in Pencoed, Wales. The Foundation estimated that the plant would produce 30,000 units per month, and would create about 30 new jobs.
• 15 October 2012 – It is announced that new Raspberry Pi Model Bs are to be fitted with 512 MB instead of 256 MB RAM.
• 24 October 2012 – The Foundation announces that "all of the VideoCore driver code which runs on the ARM" had been released as free software under a BSD-style license, making it "the first ARM-based multimedia SoC with fully-functional, vendor-provided (as opposed to partial, reverse engineered) fully open-source drivers", although this claim has not been universally accepted. On 28 February 2014, they also announced the release of full documentation for the VideoCore IV graphics core, and a complete source release of the graphics stack under a 3-clause BSD license
• October 2012 – It was reported that some customers of one of the two main distributors had been waiting more than six months for their orders. This was reported to be due to difficulties in sourcing the CPU and conservative sales forecasting by this distributor.
• 17 December 2012 – The Foundation, in collaboration with IndieCity and Velocix, opens the Pi Store, as a "one-stop shop for all your Raspberry Pi (software) needs". Using an application included in Raspbian, users can browse through several categories and download what they want. Software can also be uploaded for moderation and release.
• 3 June 2013 – 'New Out Of Box Software or NOOBS is introduced. This makes the Raspberry Pi easier to use by simplifying the installation of an operating system. Instead of using specific software to prepare an SD card, a file is unzipped and the contents copied over to a FAT formatted (4 GB or bigger) SD card. That card can then be booted on the Raspberry Pi and a choice of six operating systems is presented for installation on the card. The system also contains a recovery partition that allows for the quick restoration of the installed OS, tools to modify the config.txt and an online help button and web browser which directs to the Raspberry Pi Forums.
• October 2013 – The Foundation announces that the one millionth Pi had been manufactured in the United Kingdom.
• November 2013: they announce that the two millionth Pi shipped between 24 and 31 October.
• 28 February 2014 – On the day of the second anniversary of the Raspberry Pi, Broadcom, together with the Raspberry PI foundation, announced the release of full documentation for the VideoCore IV graphics core, and a complete source release of the graphics stack under a 3-clause BSD license.

Raspberry Pi Compute Module

• 7 April 2014 – The official Raspberry Pi blog announced the Raspberry Pi Compute Module, a device in the form factor of a 200-pin DDR2 SO-DIMM memory module (though not in any way compatible with such RAM), intended for consumer electronics designers to use as the core of their own products.
• June 2014 – The official Raspberry Pi blog mentioned that the three millionth Pi shipped in early May 2014.
• 14 July 2014 – The official Raspberry Pi blog announced the Raspberry Pi Model B+, "the final evolution of the original Raspberry Pi. For the same price as the original Raspberry Pi model B, but incorporating numerous small improvements people have been asking for".
• 10 November 2014 – The official Raspberry Pi blog announced the Raspberry Pi Model A+. It is the smallest and cheapest (US$20) Raspberry Pi so far and has the same processor and RAM as the model A. Like the A, it has no Ethernet port, and just one USB port, but does have the other innovations of the B+, like lower power, micro-SD-card slot, and 40-pin HAT compatible GPIO.
• 2 February 2015 – The official Raspberry Pi blog announced the Raspberry Pi 2. Looking like a Model B+, it has a 900 MHz quad-core ARMv7 Cortex-A7 CPU, twice the memory (for a total of 1 GB) and complete compatibility with the original generation of Raspberry Pis.
• 14 May 2015 – As a result of production optimizations the price of Model B+ was decreased from US$35 to US$25. Skeptics have speculated that the actual reason is competition from lower priced C.H.I.P.

See also

• RACHEL
• Comparison of single-board computers
• IOIO

Further reading

• Raspberry Pi For Dummies; Sean McManus and Mike Cook; 432 pages; 2013; ISBN 978-1118554210.
• Getting Started with Raspberry Pi; Matt Richardson and Shawn Wallace; 176 pages; 2013; ISBN 978-1449344214.
• Raspberry Pi User Guide; Eben Upton and Gareth Halfacree; 312 pages; 2014; ISBN 978-1118921661.

External links

• Raspberry Pi Foundation official website and forums
• Raspberry Pi Wiki, supported by the RPF
• The MagPi newsletter
• Raspberry Pi gpio pinout
• Raspberry Pi component map
• ARM1176JZF-S (ARM11 CPU Core) Technical Reference Manual, ARM Holdings.