A board computer refers to a complete computer built on a single circuit board. Board computers pack all the main computer components like CPU, memory, storage, IO interfaces and power regulation into a compact printed circuit board. This article provides an overview of board computer architecture, design considerations, usage applications and market trends.
Board Computer Overview
Traditional desktop and server computers utilize multiple printed circuit boards interconnected through buses and slots. In contrast, a board computer integrates key elements onto a single board:
- CPU – Central processor providing computing capability
- RAM – Volatile memory for program execution
- Non-volatile storage – Flash, disk or SSD mass storage
- I/O interfaces – USB, Ethernet, PCIe, video, audio
- Power regulation – Board power supply circuitry
Additional peripheral boards may expand functionality but core logic is on one board. Some key advantages of board computers:
- Compact size – Entire system on one board
- Minimal wiring – No need for separate backplane or riser boards
- Ruggedness – Solid integration resists shock/vibration issues
- Cost – Consolidates multiple boards into one
- Customization – Can tailor board I/O to applications
Board computers power devices ranging from industrial automation to aerospace to gaming.
Evolution of Board Computers
Board computers evolved from early SBCs designed for embedded and industrial applications:
1970s – Microprocessors enable complex logic and memory integration onto single boards.
1980s – 8-bit SBCs using CPUs like 8088 and 68000. Expand capability using ISA and STD bus.
1990s – 32-bit computing arrives. PCI and VME standards help link SBCs.
2000s – Continued miniaturization driven by consumer market enables high performance board computers.
Today – Focus on modular board computers for customization. Standards like COM Express and SMARC emerge.
Increasing integration and performance allow board computers to serve as standalone systems.
Board Computer Standards
Several board standards help create interoperability between board computer products from different vendors:
PC/104 – Legacy stacking bus pioneered board computing for embedded systems in the 1990s. Still used in some industrial applications.
COM Express – Compact form factor leveraging standard SO-DIMM connectors introduced in 2008. Available in Mini, Basic, Compact and Extended sizes.
SMARC – Solderable SMARC standard introduced in 2013. Supports ARM and x86 SOCs.
Qseven – ARM-focused, 70mm x 70mm form factor. Qseven modules plug into base boards.
SGET – Ruggedized standard from Kontron aimed at rail and other transportation usage.
Adhering to common standards helps board computer manufacturers reach more customers.
Board Computer Hardware Design
Designing a board computer requires bringing together various hardware elements:
CPU and Chipset
The CPU provides the processing capabilities. Common choices:
- ARM – Low power consumption but limited software compatibility. Popular in embedded and mobile.
- X86 – Benefits from rich legacy PC software compatibility. More power hungry. Used across industrial, medical, gaming.
The chipset or controller hub links the CPU to other device layers. May include functions like SATA, USB, Ethernet and multimedia IO.
Memory
Two types of memory are included:
RAM – Provides high speed working memory to run programs and data. SDRAM and DDR SDRAM are common.
Non-volatile Storage – Stores OS, applications, and data permanently. eMMC, SATA SSD are common as they do not require separate storage board.
Interfaces
A variety of peripheral interconnects allow linking external devices:
- USB – Universal connectivity for peripherals including mass storage
- Ethernet – Wired networking
- PCIe – High speed expansion
- SATA – Storage drives
- Video – VGA, HDMI, DP for displays
- Audio – Line in/out, microphone, speaker connectivity
- Serial – Legacy connectivity for industrial devices
Choosing the right mix of I/O allows matching the board computer to its usage environment.
Power
An integrated power supply converts external DC or AC voltage to supply stable power to board components. May include functions like:
- Rectification and filtering
- Switching voltage regulation
- Overvoltage and brown-out protection
- Supervisory functions to control power up/down sequencing
- DC-DC conversion to generate other needed voltages from main supply
Form Factor
Various standard (COM Express, SMARC) and custom form factors exist to package board computers for insertion into a rack or enclosure. Smaller boards allow more compact systems. Large boards provide flexibility for more functionality and ports.
Heatsinking Design
The high density of components on board computers requires carefully designed thermal management. Common cooling techniques include:
- Conduction – Heat spreaders on hot components conducting heat into a chassis or heatsink
- Convection – Internal airflow routed over the board and components
- Radiation – Infrared radiation dissipated through chassis openings
- Cold Plates – Direct metal contact cooling for maximum heat transfer
Thermal design is critical to ensure reliable operation and prevent throttling under maximum loads.
Ruggedizing for Harsh Environments
Board computers designed for industrial, aerospace, defense and transportation markets require ruggedization including:
- Conformal coating to resist condensation, chemicals and particles
- Reinforced soldered connections with underfill, glue or staking
- High temperature rated capacitors, ICs, laminates and solders
- Undermount technology securing components on both sides against shock/vibration
- EMI shielding around components and the PCB edge
- Hermetically sealed enclosures for moisture and gas resistance
Customization and Expandability
Board computers balance integration against customization needs:
- Fixed Configuration – Maximum integration and cost savings but limited flexibility or upgradability.
- Modular – Use of mezzanine cards or stacked boards provides expansion like multiple Ethernet ports.
- Backplanes – Allows plugging in different peripheral daughter boards like storage, graphics, comms.
- Customization – Work with ODMs/OEMs to tailor board I/O and features to specific applications.
The expandable design approach costs more but allows matching the board computer to evolving needs.
Operating System and Software
Board computers leverage standard or embedded operating systems including:
- Windows – For platforms needing PC software application support
- Linux – Open source OS with rich networking support and customization
- Real-time OS – Protects critical tasks on time sensitive platforms
- Android – Supporting touchscreens and mobile applications
- Custom Embedded OS – For highly optimized and scaled down OS needs
The OS choice depends on software requirements, performance needs and hardware ecosystem compatibility.
Usage Applications
The unique benefits of board computers make them well suited for diverse applications:
Industrial Automation – Rugged board computers provide distributed intelligence and control. They serve as compact industrial controllers and HMIs.
Transportation – Railway, marine and aerospace rely on rugged, SWaP optimized SBCs to consolidate control electronics.
Medical – Hospital systems like imaging leverage board computers for data processing and analysis.
Defense – Rugged computer solutions meet harsh environmental requirements.
Digital Signage/Kiosks – Compact board computers drive interactive public information displays.
Gaming Machines – Hobbyist gaming platforms integrate on board logic, graphics and storage for portability.
Robotics – Onboard systems guide autonomous navigation, image processing, and coordination.
Trends Driving Adoption
Several technology and market forces are increasing adoption of board computers:
- Processing Performance – More CPU cores, memory, GPU and accelerator integration allow board computers to take on demanding workloads. ARM offers low power options.
- Storage Density – Large amounts of onboard eMMC, SSD, and NVMe flash provide storage capacity previously requiring separate disks.
- Wireless Networking – Built-in WiFi and cellular enable untethered operation.
- OS and Software Maturity – Mature embedded Linux ecosystem and support for containerization.
- Customization – ODM services allow tuning board I/O and features to applications.
- SWaP Optimization – Size, weight and power reductions for space and energy constrained platforms.
- Edge Computing – Board computers serve well as intelligent remote IoT gateways and hubs.
- Ruggedization – Packaging and conformal coatings allow reliable usage under harsh conditions.
Conclusion
Board computers offer a unique approach to system architecture by integrating entire computers onto compact printed circuit boards. Continued technology advancements allow increased performance and customization. Board computers will continue growing in capabilities and spanning applications from industrial controls to high speed data analytics to rugged defense systems and beyond.
What is a Board Computer? – FAQ
Q: What are the main differences between board computers and traditional computer architectures?
A: Board computers consolidate all core functions onto one board vs multi-board architectures linked by buses in traditional PCs and servers. This allows greater customization but less expandability.
Q: What are some key considerations when selecting a CPU for a board computer?
A: Performance needs, power budget, software compatibility, OS support, cost, onboard peripherals needed, thermal design, upgradability requirements.
Q: What types of external peripherals or accessories are commonly connected to board computers?
A: Storage drives, monitors, industrial control systems, networking devices, IO modules, application specific daughterboards. Wired and wireless options available.
Q: Why are board computers well suited for rugged industrial applications?
A: Integration onto one board increases reliability by eliminating connectors and cabling that can fail. Rugged packaging helps withstand harsh vibration, shock, and thermal environments.
Q: What are the advantages of a modular board computer architecture vs a fixed configuration?
A: Modular mezzanine card expansion allows adding capabilities like wireless or specialized IO interfaces. However, there are costs to enabling modularity, both in hardware design and software integration.
