ARM CTO: power surge could create 'dark silicon'

SANTA CLARA, Calif. — Without fresh innovations, designers could find themselves by 2020 in an era of "dark silicon," able to build dense devices they cannot afford to power, according to the chief technology officer of ARM Ltd. The warning came amid much discussion of the future of both FPGAs and netbooks at the annual ARM technical conference here.

In a decade, 11nm process technology could deliver devices with 16 times more transistors running 2.4 times as fast as today's parts, said Mike Muller in a keynote address. But those devices will only use a third as much energy as today's parts, leaving engineers with a power budget so pinched they may be able to activate only nine percent of those transistors, Muller said.

Researchers are working on a variety of techniques so power limits do not strangle future designs, Muller said. They include use of more dynamic power management techniques at the system and task level, energy recycling on chip and stacked die with wireless interconnects.

Mike Muller, CTO, ARM

"Some local ultrawideband network is best way to do [3-D chip stacks] to resolve yield and interconnect problems," Muller said.

In a separate roundtable discussion, Xilinx clarified the goals of its collaboration with ARM announced earlier this week. The company is basically re-booting its efforts to create an SoC environment for its FPGAs substituting ARM cores and an updated version of the AMBA bus for the PowerPC and IBM Core Connect bus Xilinx has been using to date.

ARM and Xilinx have been working together for about a year and plan to make their first products available in 2010 using the next-generation AMBA bus now in a late stage of development. The next-gen AMBA will have new coherency features for use as an on- or off-chip bus; be backward compatible and be configurable to work at different widths and with ARM, PowerPC or Xilinx MicroBlaze cores.

In tandem with its adoption of the nex-gen AMBA bus, Xilinx is embracing more open EDA tools and formats such as the IP Exact description of core metadata. "We're trying to build a system that can be a repository of more intellectual property and AMBA is one of the ways to do that," said Vin Ratford, vice president of marketing and business development at Xilinx.

ARM was not the only company eyeing FPGAs at the event. Cypress Semiconductor may add FPGA capabilities in a future version of its Programmable System on Chip (PSoC) family.

T.J. Rodgers, CEO, Cypress Semiconductor

"I think we have microcontrollers covered so now I want to move PSoC in a new direction," said T.J. Rodgers, chief executive of Cypress in a keynote. "The patent on the FPGA has expired, so there's nothing preventing us from putting some of that in these chips in the future," he added.

DSPs and Ethernet MACs are among the other blocks Cypress may integrate in PSoC devices in the future. "We are literally scratching our heads right now and open to new ideas," he said.

At the systems level, ARM/Linux mini-notebooks from Taiwan contract design and manufacturing houses littered the show floor. Muller showed a Foxconn system using an Nvidia Tegra processor to run Adobe Flash 10 video, a key missing piece of the software stack for such systems to date.

Other ultra thin-and-light mini-notebook designs were on the show floor from Pegatron, Quanta and others using ARM-based processors from Freescale, Marvell and Texas Instruments. The used a variety of operating systems ranging from Google Android to Ubuntu Linux and Windows CE.

Foxconn's Mobinnova netbook uses the Nvidia Tegra processor to run Adobe Flash 10 video, one of many thin-and-light ODM designs for mini-notebooks using an ARM processor on display at the event.

Mentor Graphics said it will roll out before the end of the year a version of its Android Developer's Kit for the PowerPC and a version for ARM Cortex chips before April. The environment, already available in a version for Mips cores, aims to help engineers customize Android for devices other than handsets.