The Emergence of PCI Express* in the Next Generation of Mobile Platforms

The PCI Express architecture, both as a unified foundation of I/O, graphics, and networking interconnections, and as a preeminent building block on chip-to-chip, board-to-board, and system-to-system, is widely adopted by multiple market segments in the computing and communication industries. PCI Express architecture is a state-of-the-art serial interconnect technology that keeps pace with recent advances in processor and memory subsystems. From its initial release at 0.8 V, 2.5 GHz, the PCI Express technology has evolved to the general-purpose interconnect of choice for a wide range of applications, including graphics, storage, networking, etc. The PCI Express architecture retains the familiar PCI software and configuration interfaces for seamless migration and adoption in desktop and mobile PC platforms, enterprise servers and workstations, and, increasingly, a wide range of communication and embedded systems. The PCI Express technology addresses requirements from multiple market segments in the computing and communication industries, and it supports chip-to-chip, board-to-board, and adapter solutions at an equivalent or lower cost than existing PCI designs. Currently, PCI Express architecture supports a 2.5 GT/s signaling rate that yields 500 MB/s bandwidth per lane and a maximum bandwidth of 16 GB/s in a 32-lane configuration. Consistent with the expected cadence of I/O performance progression, the next generation of the PCI Express ∗ Other brands and names are the property of their respective owners. interconnect will support a signaling rate of 5 GT/s, doubling the performance of the existing links. The PCI Express interconnect provides numerous architectural improvements over existing I/O technologies. It defines a native hot-plug scheme, enables aggressive power management, provides advanced Reliability, Availability, and Serviceability (RAS) and Quality of Service (QoS) features, and simplifies PCB layouts. In this paper, we discuss the unique, universal capabilities and values of PCI Express technology emerging in the next generation of mobile platforms. We focus on PCI Express architecture, power management, and mobile applications such as graphics, networking, and form factors including the ExpressCard module as well as future form factors such as the PCI Express Wireless Card and the PCI Express Mini Card. Finally, we cover the next generation of mobile PC platforms built on the Intel Centrino mobile technology.