Mobile devices are continuing to undergo rapid adoption in the marketplace, as well as an evolution in features and functions. As consumers migrate more of their daily tasks from desktop to mobile platforms, they have come to expect their mobile devices to perform like PCs. Indeed, underlying technologies and standards have evolved such that mobile devices are on a path to marry PC-class performance with the best features of smartphones and tablets.
PCIe has long been a backbone interface in the PC world. With the advent of M-PCIe - a specification for utilizing the PCIe architecture over the MIPI M-PHY physical layer - mobile device designers can now take advantage of an expansive ecosystem tied to PCIe. This ecosystem complements advances in mobile processor and memory technologies to deliver the portability, battery life, scalability, interoperability, and processing power to support both business and consumer applications.
The MIPI Alliance’s UniPro specification defines a layered protocol for interconnecting devices and components within mobile device systems. By simplifying and unifying the interconnection of peripherals, the UniPro specification can decrease time to market and lower design costs while maintaining a high level of performance.
Another emerging protocol is USB SSIC, which uses the MIPI M-PHY and is based on the USB 3.0 protocol. Defined by the USB Implementers Forum, SSIC defines a chip-to-chip USB-based internal interconnect for mobile devices. In addition, there is the LLI protocol, also developed by the MIPI Alliance primarily for sharing DRAM memory between the application processor and the modem/baseband processor, resulting in significant cost reduction of mobile devices.
Let’s take a closer look at the advantages and disadvantages of each mobile protocol.
M-PCIe: bringing PC-class performance to the mobile platform
The chip design world has certainly embraced PCIe—the bus standard that supports the performance scaling and throughput that define desktop systems. PCIe has emerged in almost every market segment, from networking to gaming, and includes application-specific “add-on” protocols like