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BeagleBones, Raspberry Pi & mbed
On one level there seems to be a battle going on at the moment for who can dream up the oddest name for their microprocessor development tools. On another more technical level things are hotting up.
The BeagleBone is a spin-off from the popular BeagleBoard and makes a big play for the advanced end of the now considerable world-wide Arduino following. On the face of it, this is a David and Goliath situation, but will the plucky David (Arduino) find himself blown away this time by the mighty Goliath (Texas Instruments)? After all, the Arduino Uno board only has a puny 8-bit AVR microcontroller and it’s up against a TI AM3358 ARM Cortex-A8 cored 32-bit monster. Of course, it’s no contest, but fortunately they are targetting different groups. The Arduino is very suited to the beginner and yet the increasing number of expansion boards (Shields) allow some sophisticated projects to be undertaken. The BeagleBone is obviously aimed at students and hobbyists moving on to much more advanced applications, usually involving multimedia running under Linux.
At the heart of (Raspberry Pi) is a microprocessor featuring what is rapidly becoming inevitable: an ARM processor core. The Broadcom BCM2835 microprocessor device on the ‘PI uses the ARM1176JZF-S variant. The ARM 11 represents serious muscle with a 32-bit instruction set, 16-bit Thumb instructions for more efficient use of code space and Jazelle technology providing, in effect, a hardware bytecode interpreter for Java-based programs. In addition, the ‘F’ in the part number informs you that a hardware floating-point maths unit is also provided. The Broadcom chip features something else though: a very powerful multimedia processor unit. Take this chip and add 256Mbytes of RAM, video, audio, HDMI and Ethernet connectors and you have a tiny board capable of running some sophisticated gaming software under Linux.
Now this sounds a lot more like serious competition for the BeagleBone, except for the price and the target market. The ‘Pi is actually being made on a charitable basis for about a quarter of the price of a BeagleBone for supply to schools in third-world countries, although all buyers will be able to benefit from this low price. At the time of writing I don’t think the sale mechanics have been finalised, but may involve the ‘buy two, give one away’ principle.
While Raspberry Pi and BeagleBone slug it out, Arduino does have some competition with a whole raft of clones featuring rather more powerful processors: ARM 7, ARM 9, even a PIC32. However another little board making quite an impression in the Arduino arena is the (mbed) module. All the software development tools are free and on-line, so you can develop and program code into the mbed module anywhere you can get an Internet connection. The mbed website works as a social network and provides instant access to other scarily clever people working on innovative projects. The mbed uses an ARM Cortex-M3 processor from NXP confirming ARM’s march to world domination.
Never has there been so much choice in microprocessor development – provided you like ARM-core based products!