The discerning nerd's guide to Raspberry Pi hardware (2016 mid-year edition)

If you don't know your Model A from your Zero from your generation 3 Model B, this is the guide for you.

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Credit: Mark Gibbs
Hardware

In my "Ultimate Guide to Raspberry Pi Operating Systems" (Part 1, Part 2, and Part 3) I listed pretty much every noteworthy operating system and OS variant available for the Raspberry Pi family of single board computers. But what of the hardware all this OS goodness runs on? It's not like there's just one Raspberry Pi board. So, if you don't know your Model A from your Zero from your generation 3 Model B, this is the guide for you.

Also make sure you check out my 7 ways to make your IoT-connected Raspberry Pi smarter and 9 Raspberry Pi programming tools bundled with Raspbian, both of which are full of Raspberry Pi and Internet of Things goodness.

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Credit: Mark Gibbs
The Raspberry Pi Family

The boards above are ordered by release date with the oldest model at the top left and the newest at the bottom right. While the oldest models (A and B) are still available in limited quantities, there's little reason to buy them as the newer and more powerful versions are offered at the same price. Note that Raspberry Pi boards are also manufactured in China but it's easy to distinguish them because they don't have FCC/CE marks and the PCBs are usually (and appropriately) red. Also note that it’s not legal to import Chinese boards into the EU, the USA, and some other parts of the world.

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Credit: Mark Gibbs
Raspberry Pi boards feature summary

The table above summarizes the main features of the Raspberry board lineup. Since the Raspberry Pi's launch in early 2012, the sophistication and power of the products has increased phenomenally while the prices have remained in more or less the same ballpark. The exception is the Zero, which is remarkable for its power combined with an incredibly low price.

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Credit: Mark Gibbs
Raspberry Pi pricing

In the US, you can purchase Raspberry Pi boards from two distributors; element14 and Allied. The authorized distributor in the UK is RS Components. In China and Taiwan, distributor (and for some boards, the manufacturer as well) is Egoman Technology Corp.

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Credit: raspberrypi.org
First Generation Raspberry Pi Processor, the Broadcom BCM2835 SoC

The Broadcom BCM2835 System on a Chip (SoC) is used in the Raspberry Pi Model A, B, B+, Compute Module, and Raspberry Pi Zero. Pictured above is a Raspberry Pi Zero showing the Broadcom BCM2835 SoC underneath an Elpida B4432BBPA-10-F 512MB memory chip (Raspberry Pi's use RAM chips from several vendors including Elpida -- now part of Micron -- and Samsung). The Broadcom BCM2835 includes an ARM1176JZF-S Processor (ARMv6, 700 MHz except for the Zero which runs at 1GHz, 32-bit, single-core) and a VideoCore IV graphics processing unit.

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Credit: raspberrypi.org
Second Generation Raspberry Pi Processor, the Broadcom BCM2836 SoC

The Broadcom BCM2836 System on a Chip (SoC) is used in the Raspberry Pi Model 2B and includes a Cortex-A7 processor (ARMv7-A, 900 MHz, 32-bit, quad-core) and a VideoCore IV graphics processing unit.

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Credit: raspberrypi.org
Third Generation Raspberry Pi Processor, the Broadcom BCM2837 SoC

The Broadcom BCM2837 System on a Chip (SoC) is used in the Raspberry Pi 3 Model B and includes a Cortex-A53 processor (ARMv8-A, 1.2 GHz, 32- or 64-bit, quad-core) and a VideoCore IV graphics processing unit.

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Credit: raspberrypi.org
Raspberry Pi 1 Model B

The first member of the Raspberry Pi family, the Raspberry Pi Model B, started shipping in April 2012. Based on the Broadcom BCM2835 SoC (in the photo the Broadcom chip is underneath the Samsung memory chip) it comes with: composite video output (RCA jack); HDMI 1.3 output; analog audio via 3.5 mm phone jack; digital audio via HDMI; for revision 2 boards, I²S audio input and output; two USB ports; an SD/MMC/SDIO card slot; and a 10/100 Mbps Ethernet port. Initially the model B shipped with 256MB of RAM, but the Oct. 15, 2012 revision of the design upped that to 512MB. The General Purpose Input Output (GPIO) header is the 26-pin P1 design.

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Credit: raspberrypi.org
Raspberry Pi 1 Model A

Just to confuse everyone, the Raspberry Pi Model A first became available on Feb. 4, 2013, some 112 days after the Raspberry Pi Model B became available. The only difference between the two boards, other than a lower price, is the lack of an Ethernet port (note the empty pad at the bottom right of the board) as well as a single USB port. This board had 256MB of RAM, which along with the other differences, resulted in lower power consumption than the Model B.

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Credit: wikipedia.org
GPIO Header for Raspberry Pi 1 Models A and B

Arranged in a 2-by-13-pin configuration, the breakout header (labeled P1 on the board) provides eight General Purpose I/O lines as well as access to the I²C (Inter-Integrated Circuit, a multi-master, multi-slave, single-ended, serial computer bus), SPI (Serial Peripheral Interface bus, a synchronous serial communication interface specification used for short distance communication), and UART interface (Universal Asynchronous Receiver Transmitter which provides asynchronous RS232 or RS485 communications), along with +3.3 V, +5 V and GND supply lines.

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Credit: raspberrypi.org
Raspberry Pi Compute Module

Announced on April 7, 2014, the Raspberry Pi Compute Module was designed for industrial use and embedded applications. The Compute Module, which provided the guts of a first generation Raspberry Pi (it has a Broadcom BCM2835 SoC, 512MB of RAM, and 4GB eMMC Flash memory for booting the operating system), is in the form factor of a standard DDR2 SODIMM package. Two MIPI display interfaces for raw LCD panels were added and for increased input/output facilities (46 GPIO), the Raspberry Pi Compute Module can be mounted on the Compute Module IO Board.

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Credit: raspberrypi.org
Raspberry Pi Model B+

Released in July 2014, the Raspberry Pi Model B+ uses the Broadcom BCM2835 SoC and comes with composite video output (TRRS jack); HDMI 1.3 output; analog audio via 3.5 mm phone jack; digital audio via HDMI; for revision 2 boards, I²S audio input and output; four USB ports; an SD/MMC/SDIO card slot; and a 10/100 Mbps Ethernet port. Initially the model B shipped with 256MB of RAM but the Oct. 15, 2012, revision of the design upped that to 512MB. The General Purpose Input Output (GPIO) header is the 40-pin J8 design. The friction-fit SD/MMC/SDIO card slot was replaced with a MicroSDHC slot.

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Credit: raspberrypi.org
Raspberry Pi Model A+

Released in November 2014, the first generation Raspberry Pi Model A+ replaced the original Model A's 26-pin P1 GPIO header with the 40-pin J8 GPIO header and the RAM was upgraded to 512MB from the original Model A's 256MB. The friction-fit SD/MMC/SDIO card slot was replaced with a MicroSDHC slot, the Ethernet port removed, and the USB ports reduced to one. The USB port was also aligned with the board edge, the composite video moved to the 3.5mm jack, and the board made about 2cm shorter.

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Credit: raspberrypi.org
Raspberry Pi 2 Model B

Released in February 2015 and sporting the same form-factor as the Raspberry Pi Model B, the second generation Raspberry Pi 2 Model B got a big step-up in computing power via a Broadcom BCM2836 SoC, which increased the number of cores to four and raised the clock speed to 900 MHz. RAM was also increased to 1GB.

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Credit: raspberrypi.org
Raspberry Pi Zero

The Raspberry Pi Zero, a simplified version of Raspberry Pi A+, with a smaller footprint and much lower cost ($5), was released Nov. 26, 2015. In common with the Raspberry Pi 1 Models A+, B, B+, and B2, the Raspberry Pi Zero uses the Broadcom BCM2835 SoC but runs with a clock speed of 1GHz. It has 512MB of RAM and presents the 40-pin J8 GPIO breakout but without the header soldered on. Version 1.2 added a camera cable connector (the connector is J12 on the right of the board; note this connector does not work with the standard Raspberry Pi camera cable). Version 1.3, which looks almost identical to version 1.2, had minor cleanups such as removing unused pads.

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Credit: raspberrypi.org
Raspberry Pi 3 Model B

The third generation Raspberry Pi 3 Model B once again increased performance with the first 64-bit, 1.2 GHz, quad core processor in the family provided by the Broadcom BCM2837 SoC supported by 1GB of RAM as per the second generation Raspberry Pi 2 Model B. Other upgrades include 802.11n wireless and Bluetooth 4.1 support.

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Credit: wikipedia.org
GPIO Header for Raspberry Pi 1 Models A+, B, B+, 2B, and Zero

On the Raspberry Pi Model Arranged in a 2-by-20-pin configuration, the breakout header (labeled J8 on the board) The first 26 pins are the same as the P1 connector on the A and B boards providing backwards compatibility. The additional 14 pins provide extra GPIO and ground pins, as well as an EEPROM ID feature for auto-configuration of add-on "HAT" (Hardware Attached on Top) boards that allows the Raspberry Pi to identify a connected HAT and automatically configure GPIO pins and drivers accordingly.

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Credit: Mark Gibbs, data courtesy elinux.org
Raspberry Pi Board Revision History

There are a number of board revisions for the various members of the Raspberry Pi family and the technical details of a specific revision may be important if you're building a large number of IoT or embedded systems and want to ensure that your boards conform to a standard specification. See elinux.org's Raspberry Pi hardware history page for details of how to identify board versions and options.

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