Embedded developers must make better use of the power features available to them.
In today's embedded signal processing growth markets, the product developer's focus has shifted from performance concerns to issues of power. The performance needs of the growth markets, from consumer handheld devices to digital home entertainment and automotive entertainment and advanced safety equipment are largely satisfied with the performance levels of today's hardware solutions. If a device is comfortably delivering a media stream in real time, there's no advantage to decoding any faster.
When I talk to customers, there's more concern about increasing power efficiency. This is across the board, not just in portable battery powered devices. Some of this is definitely “green” thinking, which we support whole-heartedly, but most of the power consciousness in our customers' designs tends to be driven by battery capacity/life and thermal/power dissipation goals. At what point does a cool consumer device with a low battery life become a source of frustration? Remember the old mobile phones? “This needs to be quick, my battery . . . ” Beep. “END OF CALL.”
Vendors throughout the industry, for products from power supplies to RF blocks to audio amplifiers, are implementing low-power design techniques into their products. Embedded processor vendors are contributing their fair share.
Many of these design techniques are passive; the component uses less power due to its inherent design, due to advanced process, architecture, and circuit implementations. Low-leakage CMOS, gated clocks, etc., provide their benefits without user or program control. Everybody benefits.
Others techniques, such as variable clock frequency, variable core supply voltage, and sleep modes, require active management. They're activated under program or user control. These features can be quite effective in dynamically matching performance to workload.
Yet other aspects of design for low power depend on the art of the embedded systems programmer to make best use of chip resources (caches, DMAs, memory, etc.) to avoid wasting cycles due to inefficient processor, memory, and bus usage. This is essentially a performance tuning process where miles per gallon AND miles per hour are maximized. A detailed understanding of the device architecture and specific implementation, coupled with indepth application knowledge, results in an optimal mapping of the application to the system resources, resulting in a highly efficient design. The use of optimized software modules can yield great benefits.
While we frankly don't expect to single-handedly reverse global warming through more efficient signal-processing silicon, we do expect to significantly reduce power consumption in embedded devices. Our customers demand it. “Power” is the new “performance.”
Jerry McGuire is the vice president of Analog Devices' General Purpose DSP Group. He can be reached at .