PowerWise Interface (PWI) technology, developed jointly by National Semiconductor and ARM, is getting a push as an open standard for system power management. The technology aims to ease deployment of advanced power-management designs in handheld devices. Specifically, PWI provides an open standard for the interconnect between system-on-a-chip processors and power-management ICs.
The PWI specification defines a two-wire serial interface connecting the processor's on-chip power controller with the power-management IC's voltage regulator. This interface enables system designers to dynamically adjust the supply and threshold voltages on digital processors. The specification defines the required functionality in the PWI slave, including the operating states, the physical interface, the register set, the command set, and the data communication protocol for messaging between the PWI master and PWI slave.
For further information about the specification, go to www.pwistandard.org.