Smartphones: Where PCIe has not gone before—but will. Sooner rather than later.

Rick Merritt has just published an interesting article in EETimes: the PCI Special Interest Group (PCI SIG) expects to announce an adaptation of the ever-popular PCIe interface for mobile devices including smartphones. Merritt reports that the PCI SIG and MIPI Alliance signed a collaboration agreement on Monday, September 10 to create a version of the next-generation PCIe 4.0 spec that runs on top of the MIPI Alliance’s M-PHY. The MIPI Alliance, which oversees the development and adoption of mobile interface standard, and are there ever a lot of such standards, as you can see here from the MIPI Alliance’s Web site:

MIPI Interface Block Diagram for Mobile Devices

If you look at the diagram, you might see a glaring omission as I did. There’s no MIPI standard for connecting large amounts of RAM to the host application processor. To date, LPDDR standards have done this job and may continue to do so in the future. The addition of a PCIe protocol on top of the existing M-PHY physical layer presents another interesting possibility for a low-power interconnect spec. The MIPI Alliance’s M-PHY started as a 1.25Gbits/sec physical-layer interface and will reportedly hit 5.8Gbits/sec with a third-generation spec expected to appear next year.