Scott Fabini - Freescale COM Express White Paper

Expanding the COM Express® Specificationfor Alternative Microprocessor Architectures

Document Number: QORIQSBCWHTPPR Rev 0

2Freescale Semiconductor, Inc. and Emerson Network Power Expanding the COM Express Specification for Alternative Microprocessor Architectures

Authored by

Scott FabiniSolutions ArchitectEmerson Network Power Jim InnisSystems Engineer, Power ArchitectureFreescale Semiconductor

1 IntroductionSince its introduction in 2005, the COM Express® form factor has shown increasing market acceptance within the industry landscape. Customers have been attracted to a number of features:

and validated

These features allow vendors to focus on their strengths of generating

system integration.

The COM Express specification is built largely upon the x86 personal

the development of compatible modules using processors built on Power Architecture®, MIPS® or ARM® technologies. These System on

scalable across a wide range of markets and applications.

the COM Express form factor. Maintaining the physical aspects of the form factor is important to leverage existing investments while creating additional, more deeply embedded opportunities for the standard.

There is a desire to ensure continued compatibility with today’s standard COM Express modules. Target compatibility would entail:

functionality level

via differing definition of the CD connector

approach to meeting these goals.

This paper does not suggest abandoning COM Express compliant

implementations in a move toward even broader market adoption.

2 Addressing the design challenges

2.1 Pins that are not offered by the SoC processorThere are a number of primary signals that come to mind when first

firmware flash, generally used today for legacy SuperIOs and TPMs

the processor is exceeding internal thresholds

Embedded processors based on Power Architecture, MIPS and ARM

only.

Additionally, there are several interfaces seen to a lesser extent on SoCs than on x86 devices:

modules and flash memory.

x86 chips.

processors.

The COM Express specification allocates signals for a variety of video interfaces:


signals in the definition.

2.2 Value-added functions provided by the SoC processor, but not part of the pin-outEmbedded SoC processors of the type being considered in this paper also often have interfaces that are not covered by the COM Express specification. These include:

® or other SerDes interfaces2C interfaces

industrial communication protocols

Such interfaces should be considered to open up new application and market classes for the COM Express specification. These market opportunities include, but are not limited to, industrial control, IP telephony, networking and communications.

Note that one will see similar challenges even when considering the ®

solutions as well.

Potential solutions to this challenge:

challenges in itself: There must be available pins to do this Pins must be defined as benign when used in a compliant

carrier Pins will provide additional function when plugged into a

compatible carrier

Express standard has evolved to create new types of modules,

new interface that may not fit on the precious remaining reserved pins,

or IDE bus.

2.3 Firmware differencesFirmware for x86 processors typically provides plug and play enumeration of devices, which works well for detection and configuration of devices on the carrier in COM Express usage.

of boot media options are supported natively.

®

be used during boot up. Typical operation is headless with interface through a serial port: this should still work, but video components on

or SATA drives, will need driver code within the firmware to boot.

environment could be:

such differences in firmware behavior may need to be investigated for consideration.


3 An example SoC-based COM Express board

This COM Express board concept, based on the Freescale QorIQ

I2 ®

This is intended to exemplify the variety of interfaces that should

standard definition.

4 Wrap-upThe COM Express specification was initially targeted at x86 PC architecture processors and the form factor has gained market

could be extended to apply more generically to SoC products as well. We would like to work together with the PICMG®

Block Diagram Example: QorIQ P2020, P1020 or P1021 COM Express® Board

COMConnectors

2x RGMII

1x RGMII2x PCIe/2x 1G-SGMII

RGMII

2x 1G-T2x 1G-TPHY

Freescale QorIQ P2020/1020/1021

DDR3 800/1066

72-bit

1x PCIe

RTC/WDT

USBPHY

DVO <>LVDS

1G-T

DVO LVDSVGA

2x PCIe

SDIO/MMCSDIO/MMC

1x PCIe/1x SRIO

1G-T PHY

2x1/1x2 SRIO

Max 3 Ethernets total

2x PCIe2x PCIe 2x 1G-SGMII

2x I2C

SPI (3 CS#)

Local Bus

2x IEEE® 1588

SD/MMC

1 USB 2.0 ULPI

2x UART(Tx/Rx/CTS/RTS)

4x SERDES

3x 1G-RGMII

4x PCI Express® (PCIe)4x Serial RapidIO® (SRIO)

I2CI2C

RTC_CLK

USB 2.0 ULPI 5x USBHubUSB 2.0 4x USB 2.0

USBPHYUSB 2.0 ULPI

2x UART (Tx/Rx/CTS/RTS/)SPI

8x GPIOLocal Bus/QUICC Engine

ResetTamper Detect

2x IEEE 1588 (Trigger/Alarm/Pulse/Clock

5x USBHubUSB 2.0 4x USB 2.0

RTC_BAT

WDT

2x I2CExpander

eMMC

GFX

SO-DIMM

JTAG/COP

DebugHeader


Home Page:www.freescale.com

QorIQ Platforms Information:

Power Architecture Information:

e-mail:[email protected]

USA/Europe or Locations Not Listed:Freescale SemiconductorTechnical Information Center, CH370

[email protected]

Europe, Middle East, and Africa:Freescale Halbleiter Deutschland GmbHTechnical Information Center

[email protected]

Japan:

[email protected]

Asia/Pacific:

Technical Information Center

Tai Po Industrial Estate,

[email protected]

For Literature Requests Only:Freescale Semiconductor

P.O. Box 5405

Information in this document is provided solely to enable system and software implementers to use Freescale Semiconductor products. There are no express or implied copyright license granted hereunder to design or fabricate any integrated circuits or integrated circuits based on the information in this document.

Freescale Semiconductor reserves the right to make changes without further notice to any products herein. Freescale Semiconductor makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does Freescale Semiconductor assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without

or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. Freescale Semiconductor does not convey any license under its patent rights nor the rights of others. Freescale Semiconductor

in systems intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the Freescale Semiconductor product could create a situation where personal injury or death may occur. Should Buyer purchase or use

application, Buyer shall indemnify and hold Freescale Semiconductor and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death

alleges that Freescale Semiconductor was negligent regarding the design or manufacture of the part.

How to Reach Us:

QorIQ is a trademark of Freescale Semiconductor, Inc. All other product or service names are the property

Power.org word marks and the Power and Power.org logos and related marks are trademarks and servicemarks licensed by Power.org. Emerson Network Power and the Emerson Network Power logo are trademarks and service marks of Emerson Electric Co. PICMG and COM Express are registered trademarks of the

Document Number: QORIQSBCWHTPPR

Emerson Network Power

Tempe, AZ U.S.A.:

or

Paris, France:

Munich, Germany:

Tel Aviv, Israel

Hong Kong, China

Shanghai, China

Tokyo, Japan

Seoul, Korea

Documents

Scott Fabini - Freescale COM Express White Paper