Comparing Development Boards

Overview of the different boards

Development boards (more properly, microprocessor development boards) consist of printed circuit boards with a number of core components on them. These include a programming interface to simplify the process of programming the microprocessor from a PC, basic input components (which more often than not are buttons), basic output components (more often than not LEDs), input and output pins to connect the board up to peripherals such as LCD screens, temperature sensors, infrared sensors, and motors and, last but not least, a power circuit typically configured to run off a DC power supply of between 5 and 9 volts.

Prior to the advent of development boards, these additional circuitry components would need to be set up painstakingly, one by one, on a breadboard – a time-consuming and laborious business. Development boards have put paid to this tedium by ensuring that all the necessary circuitry has already been constructed and included on the board.

By far the most famous and widely used development boards today are undoubtedly Arduino microcontrollers; this is principally because they are exceptionally simple to use and, because of their open source development, relatively inexpensive as well (the recently launched Arduino Robot carries a higher price tag but also has an exceptionally versatile range of capabilities). The other development boards which have risen in prominence and will be examined here are the Raspberry Pi, the BeagleBone Black and the Atmel. There are, however, many others.

 

Technical aspects

The Arduino Robot, as with all Arduino development boards, is designed around an Atmel processor. On this occasion, two Atmel ATmega32u4 microcontrollers are at the heart of the boards and form the upper and lower levels of the device (control and motor). These 8-bit controllers come with 32KB of flash memory for data and programme storage, 2.5 KB of SRAM, 2 USB ports and a JTAG interface. The ATmega32u4 is capable of generating multiple functions in a single 16 MHz clock cycle, and additional Arduino expansion “shields” can extend the robot’s capabilities.

The dual processors equip the robot to process and make decisions on relatively big data loads and to execute a repertoire of different tasks.

The Raspberry Pi is currently available in two models, Model A (which has one USB port) and Model B (which, with its additional Ethernet capability and two USB ports, is slightly more expensive). The board integrates a 700MHz ARM1176JZF-S CPU with a Broadcom VideoCore IV GPU. It comes with 256 MB of RAM (512 MB on Model B), and is essentially designed for expansion and technological education.

The Raspberry Pi website provides three downloadable Linux distro operating systems – Arch Linux Arm, QtonPi and the Debian Squeeze. Set-up does require some familiarity with Linux, however. The Raspberry Pi’s capabilities can be expanded through its trio of headers: a MIPI camera interface, a Display Serial Interconnect (to enable connection to a mobile device) and 26-Pin GPIO (General Purpose Input Output).

The BeagleBone Black is another open source development board, this time courtesy of Texas Instruments, upon whose Sitara AM335x system-on-a-chip it is based. Powered by either a USB cable or independent 5V power supply with cylinder DC jack, the device comes with an impressive single core processor with a clock speed capability of 1GHz -– the OMAP3530 (where OMAP stands for Open Multimedia Applications Platform) . This is capable of both 3-dimensional and 2-dimensional graphics rendering via its PowerVR SGX5330 GPU from Imagination Technologies, and has an integral ARM Cortex-A8 CPU which can run several different operating systems: Symbian, FreeBSD, OpenBSD, Linux, and Android OS.

The board includes Secure Digital Input Output (SDIO) functionality via its SD/MMC card slot, a single USB port, a JTAG connection, and RS-232 serial connection. Stereo audio input and output is enabled by two 3.5 mm micro HDMI jacks. There are, in total, 92 female connector expansion pins arranged in two banks of 46 (one on side of the board), enabling easy use of plug-in add-ons known as “capes” – the Beagleboard equivalent of Arduino’s “shields”. The device has 256 MB of RAM and 256 MB of NAND flash memory courtesy of its integral PoP chip.

 

Technical differences (In table format)

Board platform

Arduino Robot

Raspberry Pi (Model B)

BeagleBone Black

OS

OSX, Windows, Linux

RISC OS, Linux

Symbian, RISC OS, Windows CE, Linux, Android

Processor

ATmega32u4 (AVR)

BCM2835 (ARM)

OMAP3530

Flash memory

32 KB

-

256 MB NAND

RAM/SRAM

2.5KB SRAM

512 GB RAM

 

USB

2

2

1

Audio

SD card

Input USC mic; Stereo out

Stereo I/O

Video

Integral LCD Display

NTSC, PAL, HDMI

S-Video, DVI-D

Expansions

Numerous plug-in “shields” for additional capabilities

LCD, OTG, JTAG, USB, SD/MMC, RS-232

JTAG, SD, 10/100 Ethernet, add-on “capes”

 

 

Product application - where the boards might be utilised

Each of the boards, while varying in expansion capabilities, are well suited to newcomers who wish to exercise their creative abilities without needing to learn the intricacies of computer programming. They are exceptionally popular amongst hobbyists, DIY enthusiasts and creative artists.

 

How the boards differ

The technology underpinning the expansion of capabilities is different in the different devices, although the underlying principles of Arduino’s “shields” and BeagleBone Black’s “capes” are similar. The microprocessors used in the different platforms also differ, as do the audio and video I/Os.

 

Current product advantages and limitations

Each development board featured here is itself under development and new revisions can be expected, as new discoveries and innovations are realised.