COM Express® is a PICMG standard that defines a Computer-On-Module, or COM, packaged as a super component. The defined interfaces provide a smooth transition path from legacy interfaces to modern differential signals. This includes SDVO, PCI Express® and Serial ATA.

New Interfaces

COM Express® defines 440 interconnect pins between the COM Express® module and the carrier board. Legacy buses such as PCI, parallel ATA and LPC are supported along with new serial high speed interfaces such as PCI Express®, Serial ATA and Gigabit Ethernet.

Legacy Free

COM Express® is a legacy free standard. Outdated interfaces such as floppy, PS/2 keyboard/mouse, LPT are no longer supported. If required, these legacy interfaces can be optionally generated on the customized carrier board.

The Type 6 pin-out definition on follows that path. IDE and 32 Bit PCI Bus are replaced by the new video interface DDI (switchable to DVI/HDMI or DisplayPort), additional PCI Express® lanes and the SuperSpeed signals for USB 3.0.

Size

COM Express® describes four different sizes. The mainly used form factors are the Compact (95x95mm²) and the Basic (95x125mm²). The primary difference between the modules is the overall physical size and the performance envelope supported by each.

Thermal Design

As with Qseven® and XTX/ETX, the COM Express® definition includes a heatspreader that acts as a thermal interface between the COM Express® module and the system's cooling solution. All heat generating components are thermally conducted to the heatspreader in order to avoid hot spots.

The heatspreaders and cooling solutions for the high power modules utilize high efficient heat pipes (congatec patented) in order to allow for maximum performance and high reliability.

PCI Express®

In addition to the 32 bit parallel PCI bus, COM Express® offers up to 24 PCI Express® lanes. This allows the customer to equip their embedded PC application with the next generation of PC performance. PCI Express® is a low pin count interface with maximum bandwidth per pin. The bandwidth scales up to 8 GBit/s per lane and direction.

GPIO

COM Express® defines freely usable general purpose inputs and outputs.

PCI Express® Graphics (PEG)

The PEG interface utilizes up to 16 PCI Express® lanes in order to drive an external ultra high performance graphic controller located on the carrier board. The PEG Port is available with the conga-BP77 Type 2 implementation and with most Type 6 modules.

USB

The Type 2 modules feature up to 8 USB 2.0 ports. New with Type 6 are the additional SuperSpeed signals for up to four USBs. Up to 4 USB 3.0 ports (including USB 2.0) and 4 USB 2.0 ports are available now.

Video Output

Common video outputs for Type 2 and Type 6 modules are VGA and LVDS for direct flat panel support. With Type 6, the Intel SDVO interface was reduced to a maximum of 1 channel. New for Type 6 is the implementation of 3 DDI (Digital Display Interface). Each of the DDI can be switched to TMDS (for DVI or HDMI) or DisplayPort. The current Intel implementation additionally allows the first DDI to be switched to SDVO mode. Future Type 6 modules will also allow for an embedded Displayport. This eDP interface will be multiplexed with the LVDS A channel.