Embedded System Module, or ESM, is a compact

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 microcontro ...

(COM) standard. An ESM module typically includes a CPU processor, memory, module-specific I/O interfaces and a number of basic front I/O connectors. They can be plugged on a carrier board or be used as a stand-alone processor card. If the ESM module is plugged on a carrier, it relies on the standard

PCI bus PCI may refer to: Business and economics * Payment card industry, businesses associated with debit, credit, and other payment cards ** Payment Card Industry Data Security Standard, a set of security requirements for credit card processors * Prov ...

as a board-to-board interface. In this case two connectors create a link to the carrier. While the "J1" connector provides a specified PCI connection, the "J2" connector brings I/O signals from the ESM module to the carrier, which then includes all necessary connectors. The signal assignment of J2 is not fixed but can be completely customized, although there are reserved pins for a 64-bit PCI bus interface. A third connector, "J3", is used for additional I/O signals if the ESM module has no front I/O. The signal assignment of this connector is fixed to support a special set of I/O functions. A large part of the I/O functions on ESMs are often controlled by an onboard FPGA component (field-programmable gate array) so that every module can easily be tailored to a specialized application through user-defined functions. Such functions are loaded into the FPGA as IP cores. Using FPGAs also reduces dependence on special controller chips which may become obsolete, thus extending the card's availability. ESMs are typically used on boards for

CompactPCI CompactPCI is a computer bus interconnect for industrial computers, combining a Eurocard-type connector and PCI signaling and protocols. Boards are standardized to 3 U or 6U sizes, and are typically interconnected via a passive backplane. The ...

and

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as well as single-board computers for embedded applications. A company standard by MEN Micro, a manufacturer of embedded computers, specifies the ESM concept and the different types of modules. The ESM specification defines one form factor for the printed circuit board: . Depending on the processor type, most ESM modules have heat sinks and can be operated in wide temperature ranges up to -40 to +85 °C. A mechanical specialty of ESM modules is that their connectors are compatible with the

PCI-104 PC/104 (or PC104) is a family of embedded computer standards which define both form factors and computer buses by the PC/104 Consortium. Its name derives from the 104 pins on the interboard connector ( ISA) in the original PC/104 specificati ...

module standard. These modules can be "stacked" onto ESM modules, e. g., for additional peripheral interfaces.

References

*Schmitz, M. (2005)
ESM Embedded System Modules Specification
MEN Mikro Elektronik GmbH. Retrieved on 2015-09-21. {{Computer form factors Motherboard form factors

See also

References