PCI-SIG “nificant” Changes Brewing in Mobile

PCI-SIG Developers Conference, June 25, 2013, Santa Clara, CA

Of five significant PCI Express announcements made at this week’s PCI-SIG Developers Conference, two are aimed at mobile embedded.

From PCI to PCI Express to Gen3 speeds, the PCI-SIG is one industry consortium that lets no grass grow for long. As the embedded, enterprise and server industries roll out PCIe Gen3 and 40G/100G Ethernet, the PCI-SIG and its key constituents like Cadence, Synopsis, LeCroy and others are readying for another speed doubling to 16 GT/s (giga transfers/second) by 2015. The PCIe 4.0 next step evolves bandwidth to 16Gb/s or a whopping 64 GB/s (big “B”) total lane bandwidth in x16 width. PCIe 4.0 Rev 0.5 will be available Q1 2014 with Rev 0.9 targeted for Q1 2015.

Table of major PCI-SIG announcements at Developers Conference 2013

Table of major PCI-SIG announcements at Developers Conference 2013

Yet as “SIG-nificant” as this announcement is, PCI-SIG president Al Yanes said it’s only one of five major news items. The others include: a PCIe 3.1 specification that consolidates a series of ECNs in the areas of power, performance and functionality; PCIe Outside the Box which uses a 1-3 meter “really cheap” copper cable called PCIe OCuLink with an 8G bit rate; plus two embedded and mobile announcements that I’m particularly enthused about. Refer to the table for a snapshot.

New M.2 Specification

The new M.2 specification is a small, mobile embedded form factor designed to replace the previous “Mini PCI” in Mini Card and Half Mini Card sizes. The newer, as-yet-publicly-unreleased M.2 card will be smaller in size and volume but is intended to provide scalable PCIe performance to allow designers to tune SWaP and I/O requirements. PCI-SIG marketing workgroup chair Ramin Neshati told me that M.2 is part of the PCI-SIG’s increased focus on mobile.

The scalable M.2 card is designed as an I/O plug in for Bluetooth, Wi-Fi, WAN/cellular, SSD and other connectivity in platforms including ultrabook, tablet, and “maybe even smartphone,” said Neshati. At Rev 0.7 now, Rev 0.9 will be released soon and the final (Rev 1.0?) spec will become public by Q4 2013.

PCI-SIG M.2 card form factor

The PCI-SIG’s impending M.2 form factor is designed for mobile embedded ultrabooks, tablets, and possibly smartphones. The card will have a scalable PCIe interface and is designed for Wi-Fi, Bluetooth, cellular, SSD and more. (Courtesy: PCI-SIG.)

Mobile PCIe (M-PCIe)

Seeing the momentum in mobile and the interest in a PCIe on-board interconnect lead the PCI-SIG to work with the MIPI Alliance and create Mobile PCI Express: M-PCIe. The specification is now available to PCI-SIG members and creates an “adapted PCIe architecture” bridge between regular PCIe and MIPI M-PHY.

The Mobile PCI Express (M-PCIe) specification targets mobile embedded devices like smartphones to provide high-speed, on-board PCIe connectivity. (Courtesy: PCI-SIG.)

The Mobile PCI Express (M-PCIe) specification targets mobile embedded devices like smartphones to provide high-speed, on-board PCIe connectivity. (Courtesy: PCI-SIG.)

Using the MIPI M-PHY physical layer allows smartphone and mobile designers to stick with one consistent user interface across multiple platforms, including already-existing OS drivers. PCIe support is “baked into Windows, iOS, Android,” and others, says PCI-SIG’s Neshati.  PCI Express also has a major advantage when it comes to interoperability testing, which runs from the protocol stack all the way down to the electrical interfaces. Taken collectively, PCIe brings huge functionality and compliance benefits to the mobile space.

M-PCIe supports MIPI’s Gear 1 (1.25-1.45 Gbps), Gear 2 (2.5-2.9 Gbps) and Gear 3 (5.0-5.8 Gbps) speeds. As well, the M-PCIe spec provides power optimization for short channel mobile platforms, primarily aimed at WWAN front end radios, modem IP blocks, and possibly replacing MIPI’s own universal file storage UFS mass storage interface (administered by JEDEC).

M-PCIe by the PCI-SIG can be used in multiple high speed paths in a smartphone mobile device. (Courtesy: PCI-SIG and MIPI Alliance.)

M-PCIe by the PCI-SIG can be used in multiple high speed paths in a smartphone mobile device. (Courtesy: PCI-SIG and MIPI Alliance.)

PCI Express Ready for More

More information on these five announcements will be rolling out soon. But it’s clear that the PCI-SIG sees mobile and embedded as the next target areas for PCI Express in the post-PC era, while still not abandoning the standard’s bread and butter in PCs and high-end/high-performance servers.