COM.0 Rev. 2.0 – What does it mean for OEMs?

Version 15

    Application  Note

    COM.0 Rev. 2.0 – What does it mean for OEMs?

    By Jack Chang, ADLINK Technology, Inc.

    The Computer-On-Module (COM) provides a convenient solution for OEMs that  need computing functionality but are not interested in investing the  time and resources into designing a single board computer. A COM based  solution allows OEMs to focus on their core competency, rather than the  design and maintenance of a single board computer. COM Express (also  referred to as COM.0) is a broadly adopted form factor that has recently  undergone an update to COM.0 Rev. 2.0.  This application note will  describe the changes made to the COM Express specification and the  ramifications of these changes for solution providers using the COM  Express standard to develop embedded products.

    COM.0 Rev. 2.0 – Future Proof

    In 2009, PICMG formed a subcommittee to update the COM Express specification based on the changes in peripherals used in modern systems. This included support for Super Speed USB 3.0, PCI Express Gen 2 signaling, as well as additional video interfaces such as DVI, HDMI and DisplayPort. The spec update created two new types to support the I/O changes: type 6 and 10. Backwards compatibility with existing Type 2 and Type 1 modules was a main objective of the specification update.

    New with COM.0 Rev. 2.0 – Type 6 and Type 10 Pin-outs

    The release of COM Express COM.0 Revision 2.0 brings Computer-on-Modules in line with current and future technology trends by providing for the latest graphics interfaces (DisplayPort/DVI/HDMI), PCI Express Gen 2, and SuperSpeed USB 3.0. The new Type 6 pin-out is based on the popular Type 2 pin-out, but with legacy functions replaced by Digital Display Interfaces (DDI), additional PCI Express lanes, and reserved pins for future technologies. The new Type 10 pin-out is based on the Type 1 pin-out with only the A-B connector that is used in the "Ultra" form factor. The Type 10 pin-out provides additional flexibility for developers by using the Type 1 pin-out's second LVDS channel, VGA and TV-out pins to support SDVO (via DDI), as well as freeing up pins previously used for SATA and PCIe in the Type 1 pin-out and reserving them for future technologies. Both of the new Type 6 and Type 10 pin-outs support the SPI Interface, which was unavailable in COM.0 Rev. 1.0.


    PCIe Lanes





    LAN Ports

    USB 2.0 /
    USB 3.0

    Display  Interfaces

    Type 1
    AB  connector

    Up to 6



    8 / 0


    Type 2
    AB/CD connectors

    Up to 22






    8 / 0


    Type 3
    AB/CD connectors

    Up to 22





    8 / 0


    Type   6
    AB/CD   connectors

    Up to 24




    8 / 4

    VGA, LVDS, PEG, 3x DDI

    Type   10
    AB   connector

    Up to 4




    8 / 0

    1x DDI

    Table 1: COM Express pin-out types and  supported features

    "Old" COM.0 Rev. 1.0 Type 2 vs. "New" COM.0 Rev. 2.0 Type 6


    Figure 1: COM Express Type 2 vs. Type 6 comparison

    "Old" COM.0 Rev. 1.0 Type 1 vs. "New" COM.0 Rev. 2.0 Type 10


    Figure 2: COM Express Type 1 vs. Type 10 comparison

    Customer Guidance for COM.0 Rev. 2.0

    Backwards compatibility was a major goal in COM.0 R2.0. Carriers boards designed to the Rev. 2.0 specification are compatible with both Rev. 1.0 and Rev. 2.0 modules (feature sets will be limited by module revision). Carriers boards designed to the Rev. 1 can work with both Rev. 1.0 and Rev. 2.0 modules. For maximum interoperability carrier board designers should:

    • Avoid using the PATA interface, use SATA
    • Avoid using the PCI interface, use PCIe
    • Use of SDVO for DVI/HDMI or LVDS will take special consideration

    The Right Size for the Right Job

    The   COM Express specification also defines three module sizes: the Compact   Module, Basic Module and the Extended Module. A fourth "Ultra" size   module supporting only type 1 and type 10 pin-outs has been presented  to  PICMG for inclusion in a future release of the specification.


    Figure 3: COM Express module sizes

    ADLINK COM.0 Rev. 2.0 Products



    Ultra size COM Express Type 10 module with Intel® Atom™ processor E6XX and EG20T PCH

    • Intel® Atom™ processor E6xx series up to 1.6 GHz
    • Up to 2 GB  soldered DDR2 SDRAM at 800 MHz
    • 24-bit LVDS and SDVO support
    • 4x  PCI Express x1 lanes
    • Optional Intel® Platform Controller Hub  EG20T for USB, LAN, SDIO, Serial & CAN bus and SATA
    • COM  Express COM.0 R 2.0 Type 10 Pin-out
    • Ultra form factor 84 x 55  mm
    • 0°C to +70°C or -40°C to +85°C operating temperature  range


    COM Express Type 6 Module with Intel® Core™ i7/i5 processor and Mobile Intel® QM67 Express Chipset

    • Intel® Core™ i7/i5 Processor (quad/dual core)
    • Mobile Intel® QM67 Express Chipset
    • Up to 16GB Dual Channel DDR3 SDRAM at 1333MHz
    • Three Digital Display Interfaces (DDI) for DisplayPort /HDMI/DVI/SDVO
    • Seven PCIe x1, one PCIe x16 (Gen2) for graphics (or general purpose x8/4/1)
    • Two SATA 3 Gb/s, two SATA 6 Gb/s, Gigabit LAN, eight USB 2.0

    Carrier Boards


    COM Express Type 1/10 Reference Carrier Board with onboard PCIe-to-PCI Bridge

    • Six PCI Express x1 (5 slots, 1 PCIe Mini Card slot)
    • PCIe-to-PCI bridge, two PCI slots
    • SDVO ADD2 card slot
    • LPC based Super I/O onboard
    • SDIO/MMC support, multiplexed on GPIO
    • Dual BIOS (LPC and SPI)
    • Conforms to PICMG COM Express Carrier Design Guide


    COM Express Type 6 Reference Carrier Board in ATX Form Factor

    • Seven PCI Express x 1 slots
    • PCI Express x16 / SDVO slot
    • Supports three Digital Display Interfaces (DDI) with HDMI/DVI/DisplayPort output
    • LPC based Super I/O
    • Dual BIOS (SPI and LPC)
    • Conforms to PICMG COM Express Carrier Design Guide