Power management method and arrangement for bus-coupled circuit blocks

Abstract

A power management system permits power-reduced operation of selected circuit blocks in a manner that requires no modification to other bus-coupled circuit blocks attempting to communicate with such selected circuit blocks. Consistent with one embodiment of the present invention, the approach is implemented in a digital electronic circuit arrangement having an accessing circuit block coupled to a clocked circuit block over a data bus. The clocked circuit block is power managed by decreasing, e.g., reducing or blocking, the clock speed to the clocked circuit block which impedes its ability communicate over the data bus. Once the clocked circuit block is set in a reduced power mode, the bus is monitored for data-access communications from the accessing circuit block to the clocked circuit block. In response to such a communication, a substitute response is generated on the data bus, directed to the accessing circuit block, and the clock speed to the clocked circuit block, is increased and brought out of the reduced power mode for further communications with the accessing circuit block.