Driven by embedded system requirements to shrink size, weight and power consumption (SWaP), today’s non-standard single-board computers (SBCs) are serving up a rich set of functionality and features.
Thriving well on their own outside the world of standards-based SBCs, today’s crop of non-standard form factor embedded computers trend toward designs that are extremely compact, and well suited for size-constrained system designs. These non-standard form factors free designers from the size and cost overheads inherent to standards-based boards that include a standard bus or interconnect architecture.
By definition the category of non-standard SBCs is open-ended and difficult to encapsulate. Among these SBCs are a variety of open-spec “hacker” style boards such as Raspberry Pi and Arduino cards. There are also SBC designs that strive to offer the smallest form factor possible—so-called “tiny” SBCs. Given that these boards tend to be literately “single board” solutions, there’s often no need to be compatible with multiple companion I/O boards.
Non-standard SBCs are distinct from Computer-on-Module (COM) boards, such as COM Express boards. COM boards are designed to provide just the computing core for a system—mainly just processor, memory and some key interface interconnect. SBCs in contrast are meant to provide complete system functionality, although that definition of “system” keeps expanding. And that’s been to the benefit of system developers looking to craft more compact system designs.
An example that illustrates the distinction between COM boards and complete SBCs is VersaLogic’s Zebra line of production-ready Arm-based embedded computers. Introduced in May, the boards feature models with either the NXP i.MX6 Solo (single core) or the i.MX6 DualLite (dual core) processors. The Zebra is rated for full industrial temperature operation (-40° to +85°C) (Figure 1). The compact 95 mm x 95 mm computer board typically consumes less than 3 W of power when operating.
Unlike many Arm-based “modules,” these Arm-based products are complete board-level computers. They do not require additional carrier cards, companion boards, connector break-out boards or other add-ons to function. For ease of mounting and future upgrades, the Zebra product conforms to the size and mounting points of the industry standard COM Compact format. Unlike proprietary-format Arm products, VersaLogic Arm boards provide a standardized mounting pattern for simplified upgrading in the future.
Both Zebra models include soldered-on memory and a variety of I/O. The on-board I/O includes a Gigabit Ethernet port with network boot capability, two USB 2.0 ports, serial I/O (RS-232), CAN Bus, I2C and SPI. An on-board 6-axis e-compass is optional. Zebra meets MIL-STD-202G specifications to withstand high impact and vibration. According to the company, the board is designed with careful component choices and long product life in mind. VersaLogic’s 10+ year life-extension program offers long production cycles free from expensive migration changes and upgrades.
SBC WITH DATA ACQ
The level of integration possible now on a small form factor board is so high that SBC vendors have begun offering more than just the typical SBC I/O function. They’re also adding extra capabilities for data acquisition and wireless support. Exemplifying these trends, Technologic Systems announced an engineering sampling program for a wireless- and data acquisition focused SBC with open specifications that runs Debian Linux on NXP’s low-power i.MX6 UL SoC. The -40°C to 85°C tolerant TS-7180 is designed for industrial applications such as industrial control automation and remote monitoring management, including unmanned control room, industrial automation, automatic asset management and asset tracking.
Similar to the company’s i.MX6-based TS-7970, the TS-7180 has a 122 mm x 112 mm footprint (Figure 2). At the heart of the board is a low-power Cortex-A7 based i.MX6 UL that enables the board to run at 0.91 W typical power consumption. The new SBC includes an FPGA. The FPGA enables the optional, 3x 16-bit wide quadrature counters, which are accessible via I2C registers. The “quadrature and edge-counter inputs provide access to dual, optional tachometers,” according to Technologic. The quadrature counters and tachometers are part of a DAQ subsystem with screw terminal interfaces that is not available on its other i.MX6 UL boards. The data acq features also include analog and digital inputs, DIO and PWM.
In terms of wireless options, the TS- 7180 provides a cellular modem socket that supports either MultiTech or NimbeLink wireless modules. Also included are Wi-Fi/Bluetooth, optional GPS and a socket for Digi’s XBee modules, which include modems for RF, 802.15.4, DigiMesh, and more. There are also dual 10/100 Ethernet port with an optional Power-over-Ethernet daughtercard.
The TS-7180 ships with up to 1 GB RAM and 2 kB FRAM (Cypress 16-kbit FM25L16B), which provides reliable data retention while eliminating the complexities, overhead and system level reliability problems caused by EEPROM and other nonvolatile memories, says Technologic. The board also provides a microSD slot and 4 GB eMMC, which is configurable as 2 GB pSLC mode for additional system integrity. The SBC provides a USB 2.0 host port, as well as micro-USB OTG and serial console ports. Five serial interfaces, including TTL and RS-485 ports, are available on screw terminals along with a CAN port. Other features include an RTC and an optional enclosure and 9-axis IMU. The board runs on an 8 V to 30 V input with optional external power supply and Technologic’s TS-SILO SuperCap for 30 seconds of battery backup.
3.5″ ALL-IN-ONE SOLUTIONS
While not an official “standard” created by any particular standards organization, the 3.5″ size remains a very popular form factor among SBCs. The 3.5″ size is close to the PC/104’s specification, and, as a result, many of the same companies manufacture them. But, unlike PC/104—3.5″ SBCs aren’t meant to be stacked. And in some cases, this 3.5″ size is more suited to today’s levels of integration. In the past, PC/104 stacks were necessary because not all the needed I/O functionality could fit on one board. But today, what used to require a stack of boards can now be integrated into a single 3.5″ SBC.
In an example along those lines, last August Advantech announced the release of its MIO-5850, a domain focused 3.5″ fanless SBC that supports 4th Gen Intel Celeron J1900 and Atom E3800 series low power consumption processors with 10 W to 12 W total power dissipation (Figure 3). MIO-5850 is designed with 2 GB or 4 GB of onboard memory and anti-vibration eMMC storage. Three GbE ports, CAN bus with isolation and 12 V to 24 V power make this SBC well suited for domain focused applications in industrial automation, transportation and outdoor self-service kiosks. MIO-5850 comes bundled with Advantech’s exclusive iManager 3.0 utilities and WISE-PaaS/RMM cloud ready solution for remote device management.
MIO-5850 is designed to fulfill a variety of vertical application needs and adopts a rich array of I/O interface including: 3 GbE ports, 1 x CAN bus with 15 kV isolation, 1 x USB 3.0, 5 x USB 2.0, 4 x COM ports and 16-bit GPIO. For extra expansion, MIO-5850 supports 1 x full-size miniPCIe, 1 x mSATA and an optional M.2 E-key. These allow various peripheral modules like Wi-Fi, 3G/LTE and additional storage to expand functionality. MIO-5850 can operate under wide temperature settings ranging from -40°C to 85°C, making it suited for use in rugged and harsh environments such as factory automation, railways, outdoor signage and kiosks.
MIO-5850 can be used in combination with Advantech’s WISE-PaaS/RMM solution and iManager 3.0. WISE-PaaS/RMM is part of Advantech’s WISE-PaaS cloud solution, which provides centralized management features including HW/SW status monitoring, remote control and system backup/recovery. It supports server redundancy and hierarchical server management, which increases service reliability and availability and helps customers incorporate IoT cloud services.
POPULAR RASPBERRY Pi
In the category of open-specification, so-called “hacker boards,” Raspberry Pi SBCs remain the most popular choice. Over the past couple years, Circuit Cellar’s partner LinuxGizmos.com has done a reader survey, and the Raspberry Pi 3 Model B has been the winner each time. The board is based the Broadcom 1.2 GHz BCM2837 processor which has 4x Cortex-53 cores and a 400 MHz Broadcom VideoCore IV GPU along with 1 GB of SDRAM. In the most recent LinuxGizmos survey last June, the RPi 3B slipped to fourth place thanks to roll out of the faster, more feature rich, and identically priced Raspberry Pi 3 Model B+.
The Raspberry Pi 3 Model B+ was announced March last year, with the same price and much the same layout and feature set of the RPi 3 Model B, but with both major and minor improvements. The 3B+ provides a faster, 1.4 GHz Broadcom SoC and pre-certified, dual-band 802.11ac and Bluetooth 4.2 (Figure 4). The LAN port has moved from 10/100 port to a USB-powered, up to 300 Mbps Gigabit Ethernet port, and there’s even a $20 Power-over-Ethernet POE HAT option. The initial PoE HAT reportedly had regulator problems, but Raspberry Pi Trading offered a refund and a repaired model is now available. Other RPi 3B+ improvements include a better PMIC, a heat spreader and 0 to 50°C support.
TINY SIZED SBCS
As the previous examples show, today’s level of electronics has enabled small SBCs to include more functionality. The other consequence is SBC designers can offer a complete computer on ever smaller form factor boards—some in the “tiny” sized category. Circuit Cellar did a Product Focus roundup of these small and tiny SBCs last August (Circuit Cellar 337). An example of this tiny style SBC is to 80 mm x 42 mm Innostick 6 launched by Shanghai Naxing Electronics (NXElec) last July (Figure 5). The board features the low-power, i.MX6 ULL, a variation on the i.MX6 UltraLite (UL) that similarly offers a single Cortex-A7 core, in this case clocked to 900 MHz.
The board ships with a choice of Yocto Project “Morty” based Linux stacks: one with X11 and one with Qtopia. Debian Stretch is also supported. Innostick 6 integrates 512 MB DDR3L and either a 16 GB or a 32 GB eMMC. There’s no Ethernet, but you get Wi-Fi and Bluetooth. The only coastline ports are the USB 2.0 host and micro-USB OTG ports. Also included on the SBC is a resistive touch-enabled LCD interface and a CSI Parallel camera interface. There are also 16- and 50- pin GPIO headers.
Another example SBC pushing the size barrier is the Nallino Core SBC from Garz & Fricke introduced in November. The SBC runs a Yocto Project based stack on NXP’s i.MX6 ULL SoC. At 113 mm x 47 mm x 18 mm, the Nallino Core is a little bigger than other “tiny” category boards, but it also offers a few more features. The 55-gram board is available in a baseline M version and a more feature-rich S model. Both clock the low power i.MX6 ULL to 792 MHz.
The Nallino Core SBC is equipped with 4 GB MLC eMMC and 512 MB RAM. The M model uses DDR3 RAM while the S provides DDR3L, which can run at 1.35 V in addition to the standard 1.5 V. The S model also offers a 1 GB DDR3L option. Both Nallino Core models provide a microSD slot, a micro-USB OTG port and a 24-bit RGB TTL display interface with support for backlit, I2C-based capacitive touchscreens up to 5 inches. You also get CAN, RS-485, RS-232 and buzzer interfaces, as well as a real-time clock.
Both versions list a 10/100 Ethernet port, although the block diagram suggests you could optionally remove this in favor of a Wi-Fi/Bluetooth option. The S version adds a USB 2.0 host port, as well as I2C, UART, SPI, and 4×4 matrix keyboard interfaces. This more fully featured model also adds a 4-wire resistive analog touch controller and a 1.5 W speaker interface. The S model supplies a wide-range 9 V to 32 V input in place of the M model’s 5 V input. Both versions support an extended, 0 to 60°C operating range.
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • FEBRUARY 2019 #343 – Get a PDF of the issueSponsor this Article
Jeff served as Editor-in-Chief for both LinuxGizmos.com and its sister publication, Circuit Cellar magazine 6/2017—3/2022. In nearly three decades of covering the embedded electronics and computing industry, Jeff has also held senior editorial positions at EE Times, Computer Design, Electronic Design, Embedded Systems Development, and COTS Journal. His knowledge spans a broad range of electronics and computing topics, including CPUs, MCUs, memory, storage, graphics, power supplies, software development, and real-time OSes.