System On a Module

From Variscite Wiki

1 System on a Module

1.1 About

System on a Module (SOM) - is a type of a single-board computer (SBC), a subtype of an embedded computer system, as an extension of the concept of System on Chip (SoC) and lying between a full-up computer and a microcontroller in nature.

Variscite's SOMs are complete computers built on a single circuit board. The design is centered on a single microprocessor with RAM, input/output controllers and all other features needed to be a functional computer on the one board. However, unlike a single-board computer, the COM module will usually lack the standard connectors for any input/output peripherals to be attached directly to the board. Instead, the wiring for these peripherals are bussed out to connectors on the board.

The SOM requires to be mounted on a carrier board (or "baseboard") which breaks the bus out to standard peripheral connectors.

Variscite's SOMs offer a dense package computer system for use in small or specialized applications requiring low power consumption or small physical size as is needed in embedded systems

Variscite's SOMs are low-power, high performance System-on-Modules which serve as building blocks and easily integrate into any embedded solution. They include an extensive range of interfaces and communication protocols and are ready to run any embedded operating system such as Linux and Windows Embedded CE

Variscite SOMs are widely used in a variaty of industrial fields such as: Medical, Agriculture, Industrial computing, Military and consumer products.

1.2 SOM's advantages in production:

1.2.1 Hardware

Design Challenges & Resources SOM Integration MCU Integration
Documentation Simplified Data Sheet Complex documentation
Reference Design Simple, cost-sensitive, smaller real-estate, ORCAD DSN format
Design review – Variscite offers schematic review for each of its customers.
Design Flexibility Medium High
Design Complexity  Low High – DDR interface, power management ..etc. 

Simple BaseBoard layout 4-6 layers, no micro-vias required, Signal integrity of DDRs done on SOM-> lower risk and cost

Complex (DDRs, Complex power lines..)
Micro vias in large size PCBs -> high cost
Signal integrity done by customer
Bring Up Short Process, focus in application specific peripherals.  Long HW -SW integration process of basic MCU peripherals.
Hardware upgrades (CPU Speed, memory Size) Variscite SOMs are pin-2-pin compatible -> Replacing SOM Full project re-spin.

1.2.2 Software

Design Challenges & Resources SOM Integration MCU Integration
Device Drivers Rich feature set, proven, device drivers for all common peripherals tested by over 100 customers Device drive modifications required, long debug & QA process.
Software Features Unique features such as: Remote software upgrades, manufacturing servers for concurrent burning at production,…etc Poor basic features supplied by IC vendor.
Software upgrades, BSP maintenance. Free Costly design process

1.2.3 System

Design Challenges & Resources SOM Integration MCU Integration
NRE costs Low High
Time to market Fast Slow
Design Risks Low  High
Future System upgrade / cost reduction Drop-in alternative SOMs Full project re-spin

1.3 Typical SOM block diagram:

SOM BD.jpg