Ten mobile vendors license chip interconnect
Intel, Samsung, LG, ST–Ericsson, Huawei’s HiSilicon Technologies subsidiary, and Via Telecom licensed C2C along with three undisclosed chip makers. The link enables a 100ns round-trip latency, so processor and modem chips can share a single DRAM.
By sharing memory, phone makers save $2 and 115mm2 in board space otherwise used by a dedicated low power DDR2 DRAM for the modem chip, according to TI.
C2C had its origins in the so-called Die-to-Die (D2D) interface TI used in it Omap 3 processors for a similar purpose. The D2D link was upgraded to high bandwidth, lower latency and support for LTE, creating C2C which TI is using in its Omap 4 and upcoming Omap 5 processors first described in February.
"We found many industry partners that had interest in the C2C interface [so it] developed into an ad-hoc standard with licensing of the IP available through TI and Arteris," said Brian Carlson, a member of technical staff at TI responsible for Omap platform marketing.
In 2009, Carlson proposed the MIPI Alliance embrace the technology as a version of that group’s emerging MIPI M-PHY interface. The group agreed, forming a working group to define what it calls its Low-latency Interface (LLI).
"Omap 5 maintains C2C support for backwards compatibility and also adds support for the new MIPI LLI interface," said Carlson. "We see both being used in the near future, with initial devices using C2C and migrating later to LLI in the next couple years," he said.
"I think you will see C2C be used in several modems and other companion devices in the next year to give a seamless, memory interface that reduces cost and board area," he added.
“C2C is an optimal solution for low latency mobile phone modem connection to applications processors because it allows us to fully reuse the same DDR pads that are available for connecting the standard dedicated modem RAM,” said Stefan Wolff, general manager for smartphones and RF at Intel Mobile Communications GmbH, formerly Infineon’s wireless group.
“Using the Chip to Chip Link allows [our] modems to connect to a wide selection of mobile phone application processors from multiple vendors, allowing our customers to choose the best products for their needs," said Wolff, speaking in a press statement.