Abstract: A method for managing power in a system, in which the system may include a first device configured to transmit serial data and a second device, coupled to the first device. The second device may include a transceiver and interrupt logic, and may be configured to activate the interrupt logic and enable a reduced power mode for the transceiver. Power consumption of the transceiver operating in the reduced power mode may be less than power consumption of the transceiver in an operating mode. The second device may also be configured to assert an interrupt signal responsive to a change in a voltage level of an input of the second device and then de-activate the reduced power mode for the transceiver responsive to the assertion of the interrupt signal.

Abstract: In an embodiment, a system on a chip (SOC) includes a component that remains powered when the remainder of the SOC is powered off. The component may include a sensor capture unit to capture data from various device sensors, and may filter the captured sensor data. Responsive to the filtering, the component may wake up the remainder of the SOC to permit the processing. The component may store programmable configuration data, matching the state at the time the SOC was most recently powered down, for the other components of the SOC, in order to reprogram them after wakeup. In some embodiments, the component may be configured to wake up the memory controller within the SOC and the path to the memory controller, in order to write the data to memory. The remainder of the SOC may remain powered down.

Abstract: In an embodiment, a system on a chip (SOC) includes a component that remains powered when the remainder of the SOC is powered off. The component may include a sensor capture unit to capture data from various device sensors, and may filter the captured sensor data. Responsive to the filtering, the component may wake up the remainder of the SOC to permit the processing. The component may store programmable configuration data, matching the state at the time the SOC was most recently powered down, for the other components of the SOC, in order to reprogram them after wakeup. In some embodiments, the component may be configured to wake up the memory controller within the SOC and the path to the memory controller, in order to write the data to memory. The remainder of the SOC may remain powered down.

Abstract: A method and apparatus for synchronizing data transfers from a first clock domain to a second clock domain includes sampling data from circuit included in the first clock domain. The clock signal from the first clock domain may then be synchronized to a clock signal from the second clock domain. The sampled data may then be captured using the clock signal from the second clock domain responsive to a detection of an edge of the synchronized first clock signal.

Abstract: An interface unit configured to perform transfers between a processor and one or more peripheral devices is disclosed. A system includes a processor, a number of devices (e.g., peripheral devices), and an interface unit coupled therebetween. The interface unit includes FIFOs for storing data transmitted to or received from the devices by the processor. The interface unit may access data from a device responsive to a request from the processor. The data may be loaded into a FIFO according to transfer parameters controlled by the device. After the data has been received by the FIFO, the interface unit may generate an interrupt to the processor. Data may then be transferred from the interface unit to the processor according to transfer parameters controlled by the processor. The interface unit may thus homogenize a processor interface to a number of different devices.

Abstract: An apparatus and method for saving power when transmitting data across a clock boundary is disclosed. In one embodiment, an apparatus includes a FIFO coupled to receive data from circuitry in a first clock domain and output data to circuitry in a second clock domain. A first control circuit is responsible for writing data into the FIFO. A second control circuit is responsible for reading data from the FIFO. If the amount of data in the FIFO exceeds a first threshold, a power management circuit may place the first control circuit in a low power state. The second control circuit may monitor the amount of data in the FIFO. If the amount of data in the FIFO falls below a second threshold, it may assert an indication to the power management circuit. Thereafter, the power management circuit may cause the first control circuit to exit the low power state.

Abstract: A method and apparatus for power managed interrupt handling is disclosed. In one embodiment, a system includes one or more agents that may invoke an interrupt request. An interrupt controller is configured to receive and process the interrupt requests. When idle, the interrupt controller may be placed in a low power state. The system also includes an interrupt power control circuit coupled to receive interrupt request indications from each of the one or more agents that may invoke interrupts. The interrupt power control circuit is configured to assert a wakeup signal responsive to receiving an indication of an interrupt request from one of the agents. If the interrupt controller is in a low power state, it may exit the state and resume operation in an active state responsive to assertion of the wakeup signal.