Computer-on-module

A computer-on-module (COM) is a type of single-board computer (SBC), a subtype of an embedded computer system. An extension of the concept of system on chip (SoC) and system in package (SiP), COM lies between a full-up computer and a microcontroller in nature. It is very similar to a system on module (SOM). A computer-on-module (COM) is a type of single-board computer (SBC), a subtype of an embedded computer system. An extension of the concept of system on chip (SoC) and system in package (SiP), COM lies between a full-up computer and a microcontroller in nature. It is very similar to a system on module (SOM). COMs are complete embedded computers built on a single circuit board. The design is centered on a 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 usually lacks the standard connectors for any input/output peripherals to be attached directly to the board. The module usually needs to be mounted on a carrier board (or 'baseboard') which breaks the bus out to standard peripheral connectors. Some COMs also include peripheral connectors. Some can be used without a carrier. A COM solution offers 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. As a COM is very compact and highly integrated, even complex CPUs, including multi-core technology, can be realized on a COM. Some devices also incorporate field-programmable gate array (FPGA) components. FPGA-based functions can be added as IP cores to the COM itself or to the carrier card. Using FPGA IP cores adds to the modularity of a COM concept, because I/O functions can be adapted to special needs without extensive rewiring on the printed circuit board. The terms 'Computer-on-Module' and 'COM' were coined by market researcher Venture Development Corp (VDC) and first appeared in VDC's report on the Global Market for Merchant Computer Boards in Real-time and Embedded Applications, published in November 2001. The terms became more prominent upon industry standardization of the COM Express format in 2005. There is no clear 'first Computer-on-Module' product, since numerous small component-like single board computers were already on the market when VDC initially introduced the term. COM Express is just one of many standardized Computer-on-module formats. Other open-spec COM standards include SMARC, Qseven, ESM, XTX, and eTX. Additionally, many manufacturers offer COMs with proprietary formats. Some proprietary COM formats have modified SODIMM and MXM edge-connector style designs, while others have arbitrary rectangular dimensions along with various types of high density board-to-board connectors. Notably, the Raspberry Pi Compute Module is designed in a 200-pin SODIMM format.