Abstract: Storage circuitry (66) may be used to store the values of fuses (77) so that storage circuitry (66) can be read instead of fuses (77). By accessing the fuse values from storage circuitry (66) rather than from fuses (77), there will be no sense current to fuses (77) that may cause marginal fuse blowage for fuses that have not yet been blown. This helps to prevent the situation in which an unblown fuse is erroneously read as having been blown. The use of storage circuitry (66) thus significantly improves the reliability of fuse module (20). For some embodiments, selection storage circuitry (64) may be used to determine whether storage circuitry (66) may be read or whether one of fuses (77) must be read in order to retrieve the desired current fuse value. The fuse value stored in storage circuitry (66) can also be used as direct hardware signals (80).

Abstract: New approaches for providing communication between multiple masters (12, 14) and one or more shared resources (24, 30, 100) are needed. One example of a resource that may need to be shared is circuitry complying with the Universal Serial Bus (USB) standard (100). The USB specification defines the use of USB endpoints as data and control channels that reside in a USB device. In some cases it is desirable to have a certain number of endpoints controlled by one processor, and other endpoints controlled by a different processor, thus providing a shared control of all the endpoints. Circuitry (402, 417, 480) may be used to provide steering for additional signals such as interrupts. Other shared resources (24, 30) may use more centralized circuitry (36) to perform a steering function for additional signals.

Abstract: Leakage current is eliminated in a memory array during a low power mode of a processing system having a processor that interfaces with the memory array. Because two power planes are created, the processor may continue executing instructions using a system memory while bypassing the memory array when the array is powered down. A switch selectively removes electrical connectivity to a supply voltage terminal in response to either processor-initiated control resulting from execution of an instruction or from a source originating in the system somewhere else than the processor. Upon restoration of power to the memory array, data may or may not need to be marked as unusable depending upon which of the two power planes supporting arrays to the memory array are located. Predetermined criteria may be used to control the timing of the restoration of power. Multiple arrays may be implemented to independently reduce leakage current.