Technical Doc

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.

Technical Doc
  • 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

COM Express Basic Size Type 7
COM Express Basic Size Type 6
COM ExpressBasic Size Type 2
COM Express Compact Size Type 6
COM Express Compact Size Type 2
COM Express Mini Size Type 10