The arrival last week of Linaro's open source 96Boards specification -- ARM's first pseudo-official SBC form factor standard -- shows that ARM is serious about bringing order to the chaotic ARM hacker board scene. 96Boards is a preemptive attempt to consolidate Linux and Android development before a new wave of ARMv8 hacker boards hits the scene later this year.
Linaro's 96Boards.org developer community and standards organization has defined a 96Boards Consumer Edition (CE) spec for ARM single board computers running Debian, Android, and other Linux-based distros. The spec defines either an 85 x 54mm or 85 x 100mm footprint, as well as standardized 40- and 60-pin expansion connectors for stackable boards. A higher-end Enterprise Edition (EE) spec will follow in the second quarter.
Meanwhile, BeagleBone manufacturer CircuitCo has announced a flagship CE-compliant board called the HiKey. Available for $129 from Arrow and Avnet, the HiKey appears to be the first 64-bit, ARMv8-based SBC to reach market. It runs on a new octacore Cortex-A53 Kirin 620 system-on-chip from Huawei’s HiSilicon processor division, the only other Linaro Core Member aside from ARM. Marvell and Action Technology are also prepping 96Boards SBCs, and AMD is developing a server-oriented product.
ARM sells a Juno Versatile Express board with its own generic octacore Juno SoC design with ARMv8 Cortex-A57 and –A53 cores, but this is a pricey, high-end development platform.
In October, Allwinner tipped a Nobel64 development board based on an upcoming ARMv8 Allwinner H64 SoC, but it has yet to reach market.
That leaves the HiKey alone for a moment as the only ARMv8 hacker SBC.
96Boards starts with ARMv8
The not-for-profit Linaro, a development firm that builds standardized, open source Linux and Android tools for ARM processors, is overseeing 96Boards.org via a new Linaro Community Board Group (LCG) that will help it certify boards for compatibility. Linaro, which was founded by ARM and its key licensees, boasts some 200 engineers and 29 members, including major vendors like Qualcomm, and is one of the top upstream contributors to the Linux kernel.
In recent years, Linaro has helped to clean up the chaotic and fragmented ARM Linux code base. Their progress has been remarkable, although compared to the x86 world, ARM Linux developers still face a more confusing array of platforms, options, and out-of-date code. Now, Linaro is aiming to standardize the community-backed SBC scene where over 40 different boards from dozens of projects and companies have created their own fragmented landscape marked by many different SoCs and expansion interfaces.
It's no accident that the first 96Boards SBC is based on a 64-bit ARMv8 SoC. The ARM single board computer scene will continue to be dominated for several years by low-cost ARMv7 boards like the Raspberry Pi, BeagleBone, and Odroid SBCs. Yet, 64-bit ARMv8 boards based on Cortex-A53 and Cortex-A72 -- ARM's newly announced Cortex-A57 replacement -- are on the way this year, starting with the HiKey.
Following x86 lead toward standardization
Embedded board standards are relatively new to the ARM world. As commercial embedded vendors have added more ARM-based boards to their collections, they have largely turned to x86-oriented standards, but community-backed SBCs go their own way and come in all shapes and sizes.
The most successful SBC specs have come not from Intel, but from relatively tiny Via Technologies, a maker of x86, and now ARM-based processors and boards. Before Via came up with the 6.7 x 6.7-inch Mini-ITX form factor over a decade ago, there were already common x86 form factors like EPIC or 3.5-inch formats. Via followed up with progressively smaller Nano-ITX and 100 x 72mm Pico-ITX form factors. A number of ARM-based Pico-ITX SBCs have reached market in recent years, but the main focus is still on x86.
SBC form-factors have never been as widely adopted in the x86 world as computer-on-module (COM) standards, such as COM Express and QSeven. The typical x86 approach is to match a standardized COM with a carrier board, and then develop a custom embedded board. By contrast, the ARM world is dominated more by SBCs than COMs, although many ARM-based COMs have arrived in recent years, including several based on an ARM-oriented SMARC form factor.
The Raspberry Pi has been the clear SBC leader, but has never quite reached the point of becoming a de facto standard. This is mostly because it has trailed on the processor side. Only recently has it come up to ARMv7 with the arrival of the quad-core Pi 2.
The popularity of the Pi, however, has inspired a number of semi-clones such as the Banana Pi and Orange Pi, which have adopted its 26-pin and new 40-pin expansion connectors. Although the 96Boards spec calls for a 40-pin connector, it appears to be incompatible with that of the Pi. This is another sign that ARM is now looking to lead the SBC scene instead of follow.
Will hackers follow?
There's no guarantee, however, that the SBC community will follow ARM. The 96Boards announcement lacked promises of support from major SBC projects or embedded firms.
No doubt, more projects will join in the effort, but many are likely to balk at the spec's restrictions. Granted, they're pretty loose – most boards are going to already have the required minimums of 512MB RAM (1GB for Android), as well as a microSD slot, WiFi and Bluetooth 4.0, HDMI or DisplayPort connections, dual USB host ports, and an OTG port. However, it's unclear if board vendors will go for all the specified pin assignments on the expansion connectors, or agree with the size and power requirements.
ARM and Linaro do, however, make a compelling case, as presented in Linaro CEO George Grey's 96Boards presentation at last week's Linaro Connect Hong Kong (see video below). By standardizing on size, expansion connectors, and basic features, 96Boards enables faster time to market, as well as the potential for a robust add-on market ecosystem, said Grey. Meanwhile, software developers can benefit from a single community website for common Linux and Android builds, as well as other downloads.
If nothing else, ARM has given itself a chance for success by getting out in front of the ARMv8 deluge rather than following the unruly masses of ARM hackers. It remains to be seen whether they will follow or cry "Standards? We don't need no stinking standards!"
Linaro CEO George Gray speaking on 96Boards at Linaro Connect Hong Kong