"Hobbyist" Boards Could Change Development
“Dot-Org” Boards Signal a Shift in Development Strategies
Open source hardware joined with open source software may be signaling a shift in the way embedded development will take place. Completely available design data for prototyping, modification and manufacturing is attracting ever more attention.
BY TOM WILLIAMS, EDITOR-IN-CHIEF
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The prototype. It doesn’t have to be pretty. The board doesn’t have to be the right size and shape. It can have wires hanging off it. It can have instruments attached to it. But it better work. A working prototype is what we all know we need to show management to get the go-ahead for investment in the manufacture of a real product.
Getting there can take many paths from software simulation to all kinds of cobbled-together hardware, or it can happen with a development kit supplied, for example, by a semiconductor manufacturer. Such development kits can be fairly inexpensive and are attractive. Quite often, however, you go out and spend $800 on a board product that closely (or not) resembles the system you have in mind and go from there. Of course at that point you lack schematics, a bill of materials (BOM) and a lot of other things that then must be done from scratch to get a design done. For a lot of developers, however, there may be some other ways opening up.
Quietly in the background there have been a number of small board-level products appearing over the past five or so years that appear at first glance to be aimed mostly at hobbyists, but which have the potential to also be of great help to the “serious developer.” They have whimsical names like “Raspberry Pi, BeagleBoard, MinnowBoard or Gizmo Board.” And they appear to have attracted dedicated, nonprofit communities around them that share ideas and designs they have done. In addition, many of them are available as open source hardware platforms, which come with large offerings of open source software, including full versions of Linux. One is tempted to call these “dot-org boards” due to the online communities that have grown up around them.
For all that, they come with serious processing power in terms of ARM or x86 CPUs—some hitting the Gigahertz range—generous amounts of onboard memory, and with signals and I/O brought out that go well beyond what one would need for PC functionality. You can do serious embedded design with most of these. And the price is right. A number of these are even available over Amazon for under $50.
Small, Cheap and Very Powerful
One of the better known of these, which is marking its fifth anniversary, is the BeagleBoard. The original BeagleBoard, designed by Texas Instruments and now manufactured by Circuitco, is USB-powered and based on TI OMAP3530, an ARM Cortex-A8 CPU running at 600 MHz with 128 Mbytes of LPDDR RAM and 256 Mbytes of NAND flash with connections for DVD-I, I2C, JTAG, USB 2.0, RS-232, S-Video and more.
A later version, the BeagleBoard-xM, adds to all the features of the original more memory (512 Mbytes) a 1 GHz ARM processor, a 4-port hub with 10/100 Ethernet, more USB ports and HD video. Then TI moved from this more multimedia
orientation to the BeagleBone series—the latest named BeagleBone Black—which is oriented more toward control applications with two 46-pin headers to bring out digital I/O signals. In keeping with its orientation toward small embedded applications, the BeagleBone is based on the ARM Cortex-M3 for power management. Finally, the latest offering, the BeagleBone Black has a 1 GHz Cortex-A8, 512 Mbytes of RAM and a 3D graphics accelerator (Figure 1). You can get it from Amazon for $49.
The latest in the Beagle line, the BeagleBone Black includes a 1 GHz ARM Cortex-A8 and 512 Mbytes of RAM along with two 46-pin headers for an abundance of control signals, as well as a 3D graphics accelerator, all for $45.
Another popular ARM-based dot-org board is the Raspberry Pi, which was designed and is supported by the Raspberry Pi Foundation. It is based on a Broadcom SoC, the BCM2835, which contains an ARM 11 core and a Videocore 4 GPU capable of BluRay quality playback and 512 Mbytes of RAM. Although the Raspberry Pi does not appear to have a corporate origin, it has a very loyal following among its Foundation members and is available in the range of $35.
There are also dot-org boards available in the x86 world, primarily from Circuitco and AMD. Circuitco, which as noted now manufactures the BeagleBoard line, also makes the MinnowBoard, which is based on a 1 GHz Intel Atom E640—with hyperthreading and virtualization technology—and the EG20T controller hub. The Atom processor also has an integrated graphics media accelerator. The MinnowBoard also boasts 1 Gbyte of DDR2 RAM and 4 Mbytes of SPI flash. It brings out a SATA2 connection, DVI via HDMI, analog audio, USB ports, a debug serial to USB conversion via a mini-USB port, and a variety of GPIO signals, PCI Express, Gigabit Ethernet and more (Figure 2).
The MinnowBoard allows development with an Intel Atom E640 running at 1 GHz and comes with a Linux distribution that is Yocto Project compatible. Expandability is available via user-designed MinnowBoard Lures.
The latest and perhaps most ambitious entry into this arena is the Gizmo Board based on an AMD Embedded G-Series APU, a dual-core x86 design with an on-chip integrated general-purpose graphics processing unit (GPGPU). The Gizmo Board is part of the Gizmo Explorer Kit available from GizmoSphere, a consortium of five sponsoring companies that include AMD, Sage Electronic Engineering, Viosoft, Texas Multicore, Timesys and SemiconductorStore.com. The board will be coupled with the AMD embedded roadmap as processors become available.
The current APU is rated at 52.8 GFLOP and a host of signals are brought out to two edge connectors, one high speed and one low speed. This includes, among others, SATA, USB, Display Port, PCIe, SPI, GPIO, PWM plus A/D and D/A. In addition there are onboard JTAG, VGA video, audio input/output, Ethernet and USB ports. The kit also contains an Explorer expansion board that can connect to the low-speed connectors. Here the user can have access to the signals by soldering components into a “sea of holes” and use of a small alphanumeric keypad and display. The kit also contains a Sage SmartProbe JTAG tool, a pre-installed copy of the SageBIOS and a 30-day trial license for their embedded development kit. A one-year extension is available for $299. A full commercial license is also available. The full Gizmo Explorer Kit is priced at $199. A GizmoSphere spokesperson explained that they aimed to price it at a point where a wife would not complain if her husband wanted to buy one and determined that more than $200 would be too expensive (Figure 3).
The Gizmo Explorer Kit from Gizmosphere brings a host of useful embedded design signals out of the AMD G-Series accelerated processing unit (APU), which also integrates a powerful graphic/numeric processing element. A variety of extensions and development tools are included with the kit.
Open Source All the Way
That last little pricing observation points the way to what may be a very major development in developing embedded systems. If these boards appear to be appealing to the hobbyist, well, they are. But it goes beyond that because hobbyists alone do not comprise a significant market to justify this effort. However, the same tinkering mentality and often the same individuals are at work in major companies on designing new products or are thinking about taking their ideas to a start-up. And there are communities of bloggers associated with each of these where one can find help, comments, tips and ideas.
That appears to be coming from a growing convergence of open source software with open source hardware. With the exception of the Raspberry Pi, we are talking about both here. And a little later we’ll look at an innovative variant in the form of a company called Gumstix. For the Beagle line, the MinnowBoard and the Gizmo Board, all the hardware documentation is freely available to the community including BOM, schematics, spec sheets and even the CAD files such as Gerber files for actually manufacturing the boards.
So not far in the future, that clunky prototype will look a lot more elegant. A design manager can easily justify a few boards or kits for the team and they can get started with the selected CPU. The choices are fairly limited today but don’t expect that to last. There is also a wealth of software available, primarily several open source distributions of Linux but also Android and some RTOSs. QNX Neutrino is available for the BeagleBone Black for example. Of course, if they really need to use commercially available licensed software, there should be no real barrier either.
So now the development team gets its prototype working and of course it is not the desired size or shape and there are a number of features available that are not used. Hardly anyone would use all of them. But they don’t have to start from scratch and design a new printed circuit board. Nor do they have to shop around to find a commercially available OEM board that most closely fits (but not quite) their needs. They can simply go to the CAD files and modify them saving work and optimizing their design.
The communities that are growing up around the dot-org boards are adding value as they go by making designs available such as add-on peripherals like displays, camera interfaces, network interfaces, Wi-Fi and GPS modules and the like. For the Beagle line they are called capes and for the MinnowBoard they are called lures. There is also a growing variety of designs that people are simply proud enough of that they want to share them.
We mentioned an innovative variant who also needs to be included in this discussion and that is Gumstix. Gumstix has a line of board-level products built around its line of ARM-based COMs called Overo and DuoVero based on TI ARM Cortex-A8 (Overo) and Cortes-A9 (DuoVero) processors. Gumstix does not disclose the internal design of the COM modules beyond the external pin-out, but the designs of its boards based on these COMs is available to the community. But beyond that, user-modified designs based on Gumstix original designs are also available.
Gumstix also has an online tool named Geppetto that allows users to take an existing design from the community database and modify it with exactly the features, size and shape desired for a given project. The user selects a design, clicks on “clone” and it is loaded into Gepetto for customization. Then for a $1,999 setup cost, Gumstix will verify the design, create the CAD files and either manufacture the boards or make the files available for contract manufacturing. Here again, developers do not start from scratch.
Gumstix has also come up with a crowd funding plan that lets a number of participants form a collective effort to pool their money to purchase a product or service together, thus reducing the individual cost. Users create community campaigns for any electronic device designed with Geppetto, whether or not the design is shared publicly. Designers choose a quantity threshold and campaign duration (between 10 and 45 days) and share a catalog link with their community. Community members then pledge to buy boards, and after the threshold is reached the boards are built. Users divide the set-up fee based on the quantity of boards ordered, and as a part of the launch, Gumstix will waive the fee entirely for campaigns that reach over 50 subscribers.
This dot-org board development is definitely something to watch. It has actually been around for a number of years, scampering around like small rodents among ponderous T-Rexes. If it catches on with semiconductor manufacturers, it could have a broad impact on the embedded development OEM board business.
Redwood City, CA.
Sage Electronic Engineering