BeagleBone Black

[Simon Ritchie]

Are there any users of the BeagleBone Black on here (and is this the correct forum to post about embedded systems)?  I've made use of one as part of a college course and I'm debating whether to continue to work with it or go for the RaspberryPi in future.

[Ron McLeod]

I am a Raspberry Pi2B user and haven't tried a BeagleBone yet - I'd be interested in hearing about the pros/cons of the current versions of Raspberry Pi and BeagleBone.

This blog post by Michael Leonard on Raspberry Pi or BeagleBone Black is a bit dated, but is probably still worth reading if you haven't already.

[Jan Cumps]

I have a BeagleBone Green since a few weeks.

[Ron McLeod]

Jan Cumps wrote:I have a BeagleBone Green since a few weeks.

What are the differences between Green and Black -- just the built-in HDMI on the Black?

[Jan Cumps]

yes, it's almost the same device. The HDMI is not there, and in its place are two Groove connectors.
I wasn't specifically looking for a Green ot a Black. I just asked in my friends group on element14 if anyone wanted to exchange a BeagleBoard for other hardware.

So I have this board now in exchange for a real-time-clock IC, an OLED display, 4 2N3055 transistors and their mounting hardware.

I want to learn linux-supported embedded systems, and also how to do real-time in linux.

I've blogged and made a movie about my very first steps (external links to element14 and youtube).

[Tim Holloway]

Ron McLeod wrote:I am a Raspberry Pi2B user and haven't tried a BeagleBone yet - I'd be interested in hearing about the pros/cons of the current versions of Raspberry Pi and BeagleBone.

This blog post by Michael Leonard on Raspberry Pi or BeagleBone Black is a bit dated, but is probably still worth reading if you haven't already.

It's dated, for sure. The new Pi 3's CPU speed approaches that of the version of the Beaglebone in the review, and of course, the Pi 2 and 3 boast more GPIO pins than the original Pi in the review. I don't know what the Beaglebone has added since that review.

Still, overall, the number of built-in I/O channels on the Beaglebone is impressive.

The "extra cost/effort" for Pi setup is a non-issue for me. I have enough USB-charged gadgets around the house that a power cable is never hard to find and a plenitude of SD cards. I can literally walk to at least 2 places where I can pick up more of them on the spot, and I live in suburban sprawl. Or, if one prefers ready-out-of-the-box Pi systems, ready-to-run starter kits are available in several flavors, even though some complain about the price.

Of course, if price is an object, there's the $5 Pi Zero.

The Pi3 3 sports standard wired and wireless Ethernet, Bluetooth, and 4 USB ports. The Beaglebone in the review didn't look like it had USB ports, which would make it difficult to attach a keyboard, if that's the case. In any event, I hope that someone can sing us the virtues of the current BeagleBone systems for a fairer comparison.

On a practical note, I've been earning my pocket money lately off Arduino and Pi projects. The sources I deal with have yet to demand a BeagleBone-based system, but your mileage may vary.

For the most part I use the Pi as a generic computer/media player. Although recently I've done some stuff that uses the GPIO, including one that uses a small OLED graphics display and a set of pushbuttons. I'm nowhere near maxing out the GPIOs on the Pi projects yet, although I do have another project that has a Pi acting as a central controller for banks of Arduino Megas where the Megas where chosen specifically because they have lots of ports.

[Jan Cumps]

Tim Holloway wrote:

... The Beaglebone in the review didn't look like it had USB ports....

It has one USB host (left upper corner in the photo of the article).

[Ron McLeod]

Tim Holloway wrote:... I do have another project that has a Pi acting as a central controller for banks of Arduino Megas

Tim - how do you interface the Pi to the Arduinos - using I2C?

[Tim Holloway]

Ron McLeod wrote:

Tim Holloway wrote:... I do have another project that has a Pi acting as a central controller for banks of Arduino Megas

Tim - how do you interface the Pi to the Arduinos - using I2C?

It would have been nice. But the Arduinos are programmed as SNMP agents, so they need to have UDP networking protocols. And while there has been a lot of discussion about doing TCP/IP over I2C or SPI, there are some technical issues. I2C has bus-mastery constraints, although TCP over token-ring has been suggested for that. SPI is even more limited, I understand. The most promising approach, in fact, seems to be something like PPP using the serial ports.

Indeed, using the Arduino UARTs to do device-to-device communications seems to be the most-favored option TCP/IP or not.

So it's going to be Arduinos with ethernet shields, a Raspberry Pi with a touch-screen, and an Ethernet switch. Fortunately, Arduino Ethernet shields are down to under $8 single-quantity. The Arduino that had onboard Ethernet was prohibitively expensive - which is probably why it was discontinued.

[Simon Ritchie]

Some great posts, thanks for replying everyone!

I've set up my BBB (I'm going to call it that just for ease of reference!) and installed Java 7u45 ARM Linux Soft Float.  This was at the recommendation of my course supervisor.  There doesn't appear to be a Soft Float version for Java 8.  Does anyone know why that might be?  What is the difference between Hard and Soft Float in this instance anyway?  I'm assuming it's a reference to floating points.

[Tim Holloway]

Usually "hard" and "soft" in floating-point refers to hardware processing versus software processing. Some systems had no floating-point hardware and could only do software floating-point. Some, like certain IBM System/360 mainframes packaged it as a separate microcode product when buying the hardware. In early microprocessor systems, it was often a discrete co-processor chip and only available on certain motherboards.

Chips are so cheap these days, it might be simply that floating-point hardware is simply a given or automatically sensed and supported if available, falling back to software if the hardware can't handle it.

[Simon Ritchie]

So is there anything I'd need to be aware of or anything I'd need to check before installing Java 8 for ARM Linux?  I'll keep the existing version of Java on the BBB but as I'm new to the technology I don't want to do something that will inadvertently damage it or corrupt its software.

[Tim Holloway]

There's something very wrong if installing the "wrong" Java can damage either hardware or software. Java is designed, in fact, in a way that permits you to maintain and use multiple Java versions on the same machine at the same time.

Linux users often do this without knowing it. A lot of modern Linux distros come with an open-source Java pre-installed (or at least installable). But I still recommend that for serious work like running a J2EE server that they download and install a commercial-grade Java such as Oracle's JDK.