A Computer-On-Module, or COM, is a Module with all components necessary for a bootable host computer, packaged as a super component. A COM requires a Carrier Board to bring out I/O and to power up. COMs are used to build single board computer solutions and offer OEMs fast time-to-market with reduced development cost. Like integrated circuits, they provide OEMs with significant freedom in meeting form-fit-function requirements. For all these reasons the COM methodology has gained much popularity with OEMs in the embedded industry. COM Express is an open industry standard for Computer-On-Modules. It is designed to be future proof and to provide a smooth transition path from legacy parallel interfaces to LVDS (Low Voltage Differential Signaling) interfaces. These include the PCI bus and parallel ATA on the one hand and PCI Express and Serial ATA on the other hand.
History
The COM Express standard was first released in 2005 by the PCI Industrial Computer Manufacturers Group (PICMG) and it sought to provide standardized module interfaces for several different target applications. It did so by defining five different module “Types” each implementing different pinout configurations and feature sets on one or two 220-pin connectors. In that way, COM Express is a standard of multiple standards. It also defined 2 module sizes (later expanded to 4) to allow additional flexibility to better serve the end application while maintaining compatibility within each module “Type.”
Size
The specification defines 4 module sizes:
- Mini: 55 × 84 mm (2.2 × 3.3 in);
- Compact: 95 × 95 mm (3.7 × 3.7 in);
- Basic: 95 × 125 mm (3.7 × 4.9 in);
- Extended: 110 × 155 mm (4.3 × 6.1 in)
Type
There are 7 different pin outs defined in the specification. The most common used pin out is type 2, Type 6 and Type 10. The most recent one is Type 7. Maximum available interfaces for the defined types:
Module Pin-out Type Overview
| Type | Connectors | PCI Express | PEG / SDVO | PCI | IDE | SATA | LAN | Display Interfaces | Serial | Other Features |
|---|---|---|---|---|---|---|---|---|---|---|
| Type 1 | A-B | Up to 6 | – | – | – | 4 | 1 | VGA, LVDS | – | – |
| Type 2 | A-B C-D | Up to 22 | 1/2 | 32 bit | 1 | 4 | 1 | VGA, LVDS, PEG / SDVO | – | – |
| Type 3 | A-B C-D | Up to 22 | 1/2 | 32 bit | – | 4 | 3 | VGA, LVDS, PEG / SDVO | – | – |
| Type 4 | A-B C-D | Up to 32 | 1/2 | – | 1 | 4 | 1 | VGA, LVDS, PEG / SDVO | – | – |
| Type 5 | A-B C-D | Up to 32 | 1/2 | – | – | 4 | 3 | VGA, LVDS, PEG / SDVO | – | – |
| Type 6 | A-B C-D | Up to 24 | 1/- | – | – | 4 | 1 | VGA, LVDS / eDP, PEG, 3 x DDI | 2 COM | 1 x opt. CAN, USB 3.0 |
| Type 7 | A-B C-D | Up to 24 | 1/- | – | – | 4 | 5 | CRT, LVDS / eDP, PEG | 2 COM | USB 3.0 |
| Type 10 | A-B | Up to 4 | -/1 | – | – | 2 | 1 | LVDS / eDP, 1 x DDI | 2 COM | 1 x opt. CAN, USB 3.0 |
Type 2
Type 7
Type 6
Type 10
Positioning
| / | SMARC | QSevens | ComExpress |
|---|---|---|---|
| Architecture | ARM & SoC | x86 | x86 |
| Typical TDP | 2 Watt (low power) | 12 Watt | 50 Watt (high power) |
| Typical SKU | Freescale ARM, TI ARM | Intel Atom | Intel Atom, Core |
| Specific I/Os | Parallel TFT, LVDS, MIPI CSI camera, MIPI display, I2S, few USB, GPIO, I2C, multiple SPI, serial ports, SDIO | PCIe, LPC, HDA, manu USB | PCIe, PCIe graphics, DDI, LPC, HDA, many USB |
| Connector | 1 x MXM3 | 1 x MXM2 | 1-2 ComExpress connector |
| Pins | 314 | 230 | 220 (type 10) |
| Height | 7.3 mm (w/o heatspreader) | 12 mm | 18 mm |
| Size | 82 mm x 82 mm (full size) 82 mm x 50 mm (short) |
70 mm x 70 mm (Q7) 70 mm x 40 mm (µQ7) |
125 mm x 95 mm (basic) 95 mm x 95 mm (compact) 84 mm x 55 mm (mini) |
| Area | 6560 mm2 4100 mm2 |
4900 mm2 (Q7) 2800 mm2 (µQ7) |
11875 mm2 (basic) 9025 mm2 (compact) 4620 mm2 (mini) |
| Vin | 1.5-5 Volt | 5 Volt | 4-18 Volt |
| Operating System | Linux, Android, WEC | Windos, WEC, Linux, QNX | Windos, Linux, VxWorks |
| Battery Lifetime | Long | Medium | Short |
Products
