Review: Beagleboard Beaglebone Black
Pi-eyed killer - or should we give Pis a chance?
It's nice to see that the broader community of Arduino, Raspberry Pi and Beagleboard Beaglebone users is a friendly and seemingly mature one.
Each of these board computers has its own adherents, but few of them seem to feel the need to engage in the kind of hair-pulling and name-calling that defined the Windows versus Mac spat of the 1990s and the Android-iOS face-offs we're seeing today.
Black adder: all you need to run the new Beaglebone is a free USB port on your computer
That said, it's hard not to start trying to stir things up a bit - and we tech journalists are certainly guilty of egging on more confrontational users - by lining these boards up against each other. Especially since, at first glance, Beagleboard's latest offering, the Beaglebone Black, seems to be out to get one over the trendy Raspberry Pi.
Comparing the two isn't entirely invidious: many folk who might have been considering the Pi for use as a very tiny desktop computer or media server, may now be thinking the Black, with its more powerful processor, might not be a better bet. Likewise, if you're seeking a compact board around which to construct a hardware project, you might well want to see which of these boards might best meet your needs.
This kind of hardware hackery is where the Black, like its predecessor, comes from. The Pi has found an audience among the "maker" community too, though its origins lie in education. Equally, it's entirely possibly that people looking to learn to code - or to encourage their kids to do so - may also be eyeing the Black and wondering whether they should pick it over the Pi.
Board members: Raspberry Pi (left) and Beaglebone Black
Personally, that's where my interest in the Black lies - though I'll consider its other roles in this review too. I bought a Pi because I wanted a platform I could use to get closer to the computer components that modern operating systems and designs hide behind hardware abstraction layers: a world of UARTs and I^2C buses, and of assembly language coding, but also of breadboards, LEDs, resistors and other simple electronics.
Oh, and I'm trying to get my nipper to learn Python too.
When I bought my Pi, I was aware of the original Beaglebone, but the buzz over here was really surrounding the Pi, and that's why I went for the home-grown option. But should I switch allegiance to the new Beaglebone?
The Black, then, is a tiny board based around a Texas Instruments Sitara AM335x system-on-a-chip, itself derived from ARM's Cortex A8 architecture. Its single processor core can clock to 1GHz, it has a PowerVR SGX 530 graphics core, plus all the memory, display and connectivity IO control you'd expect from a modern system-on-a-chip. Beagleboard has hooked the AM3359 up to 512MB of low-power DDR3L memory clocked at 400MHz, a USB 2.0 port for peripherals, a 10/100Mbps Ethernet jack for networking and a (spring-loaded) Micro SD slot for storage. You can hook up a TV or monitor using HDMI.
The Black has many, many IO pins, in two arrays of female ports top and bottom in this picture
For the hardware hackers there are no fewer than 92 expansion pins, exposed through the two banks 46-pin female connectors on either side of the board, with six further serial pins for debugging. A point to note is that the construction of the Black's expansion makes it easy for extra circuit boards to clip securely into both of IO slots, whether they use all or the pins or not. Beagleboard calls these add-ons "capes" and there are a fair few on the market already that add to the Black's features. That's true of the Pi too, but the Beagleboard solution is more elegant and better suited to assembling stacks of boards.
The Black is more powerful and more capable than its predecessor, but it's less well connected than the Pi, particularly the Model B. The Black has only one USB port for peripherals, which is disappointing since there's room on the board for a double-decker two-port block of the kind the Pi offers. These are no taller than the Ethernet port. Two USB ports is the bare minimum, particularly if, like me, you want to hook up a keyboard and mouse without having to resort to a powered USB hub, though that's an essential add-on if you want also wireless networking and Bluetooth on your Pi.
The Black has a number of power feeds. The most obvious one is a cylinder DC jack, which initially annoyed me because I don't have any compatible AC adaptors kicking around. Why, I cried, doesn't it use a micro USB slot like the Pi does? I have plenty of USB transformers and micro USB cables. In fact, the Black does, sort of: its second power port is a mini USB port and if you don't have a suitable cable already, no matter: the Black comes with one. And if mini USB and cylinder ports weren't sufficient, there's an unsoldered four-pin header on the board for battery power connections.
A second USB host port would have been nice
I did need to buy a micro HDMI cable in order to hook the Black up to my TV. I was going to buy a simple adaptor for a regular HDMI cable, but it's a good job I didn't: the USB and HDMI ports on the Black are so close I wouldn't have been able to get plugs into both. Meanwhile, the Pi has a full HDMI connector which is spot-on for modern TV connections, but if you have an older telly it also has composite-video output and, for good measure, a 3.5mm analogue headphone jack. These the Black lacks. Incidentally, the Pi uses full-size SD cards for storage, but that's neither better nor worse than the Black's Micro SD.