Definition
A computer‑on‑module (COM) is a compact, fully functional computer subsystem that integrates a processor, memory, storage interfaces, and essential input/output (I/O) controllers onto a single printed circuit board (PCB). The module is designed to be mounted onto a carrier board or a custom host platform, providing the core computing capabilities while leaving peripheral and application‑specific circuitry to the host design.
Overview
COMs are employed in embedded systems where space, power consumption, and rapid time‑to‑market are critical. By encapsulating the core processing elements on a small module—typically ranging from a few square centimeters to roughly 100 mm²—manufacturers can standardize the computing layer across multiple product families. The host or carrier board supplies power, additional I/O (such as Ethernet ports, USB, video connectors, and specialized interfaces), and mechanical mounting points. This modular approach enables designers to upgrade or interchange processing capabilities by swapping the COM without redesigning the entire system.
Etymology/Origin
The term combines “computer,” indicating a general‑purpose processing unit, with “module,” denoting a self‑contained, replaceable hardware component. The concept emerged in the early 2000s as a response to the growing demand for highly integrated yet flexible embedded platforms. It parallels the terminology “system‑on‑module” (SOM), which emphasizes the inclusion of a complete system (including the operating system support) on a single board.
Characteristics
- Form factor: COMs are produced in standardized sizes (e.g., 30 × 30 mm, 55 × 55 mm) and often conform to industry mechanical specifications such as COM Express, SMARC, or Qseven.
- Processor families: They may incorporate a variety of CPU architectures, including x86 (Intel Atom, Core series), ARM Cortex‑A/R/M, PowerPC, or RISC‑V cores.
- Memory and storage: Typical configurations include DDR/LPDDR RAM and either soldered flash storage or interfaces for external eMMC, SD, or SATA devices.
- I/O integration: Core I/O controllers are provided on‑board, such as USB, PCIe, UART, SPI, I²C, and Ethernet MACs. Additional peripheral support is realized through the carrier board.
- Power requirements: COMs operate at low power levels, often less than 10 W, making them suitable for battery‑powered or thermally constrained applications.
- Operating system support: They are compatible with mainstream operating systems (e.g., Linux, Windows Embedded, Android) and may include reference BSPs (Board Support Packages) from the module vendor.
- Scalability: Upgrading to a more powerful processor can be achieved by replacing the COM while retaining the existing carrier board, reducing redesign costs.
Related Topics
- System‑on‑module (SOM) – a closely related concept emphasizing a complete system (hardware and software) on a single board.
- Computer‑on‑module standards – specifications such as COM Express, SMARC, Qseven, and CoreExpress that define mechanical, electrical, and connector requirements.
- Embedded computing – the broader field encompassing the design and deployment of computers within dedicated devices.
- Carrier board – the custom PCB onto which a COM is mounted, providing additional I/O, power regulation, and mechanical integration.
- Single‑board computer (SBC) – a complete computer on a single board, comparable to a COM but typically used as a standalone device rather than as a modular component.