Abstract: Power saving systems and methods for Universal Serial Bus (USB) systems are disclosed. When a USB physical layer (PHY) enters a U3 low power state, not only are normal elements powered down, but also circuitry within the USB PHY associated with detection of a low frequency periodic signal (LFPS) wake up signal is powered down. A low speed reference clock signal is still received by the USB PHY, and a medium speed clock within the USB PHY is activated once per period of the low speed reference clock signal. The medium speed clock activates the signal detection circuitry and samples a line for the LFPS. If no LFPS is detected, the signal detection circuitry and the medium speed clock return to low power until the next period of the low speed reference clock signal. If the LFPS is detected, the USB PHY returns to a U0 active power state.

Abstract: Power saving systems and methods for Universal Serial Bus (USB) systems are disclosed. When a USB physical layer (PHY) enters a U3 low power state, not only are normal elements powered down, but also circuitry within the USB PHY associated with detection of a low frequency periodic signal (LFPS) wake up signal is powered down. A low speed reference clock signal is still received by the USB PHY, and a medium speed clock within the USB PHY is activated once per period of the low speed reference clock signal. The medium speed clock activates the signal detection circuitry and samples a line for the LFPS. If no LFPS is detected, the signal detection circuitry and the medium speed clock return to low power until the next period of the low speed reference clock signal. If the LFPS is detected, the USB PHY returns to a U0 active power state.

Abstract: Aspects disclosed in the detailed description include high-frequency signal observations in electronic systems. In this regard, a high-frequency signal observation circuit is provided in an electronic system to enable high-frequency signal observations. In one aspect, the high-frequency signal observation circuit comprises an observation signal selection circuit. The observation signal selection circuit is programmably controlled to select an observation signal among a plurality of electronic input signals (e.g., control signals) received from the electronic system. In another aspect, the high-frequency signal observation circuit is configured to utilize a bypass data path, which is routed around serializer/deserializer (SerDes) logic in the electronic system, to output the observation signal for observation. By programmably selecting the observation signal and outputting the observation signal via the bypass data path, it is possible to examine accurately any high-frequency signal (e.g.

Abstract: Aspects disclosed in the detailed description include apparatuses, methods, and systems for glitch-free clock switching. In this regard, in one aspect, an electronic circuit is switched from a lower-frequency reference clock to a higher-frequency reference clock. An oscillation detection logic is configured to determine the stability of the higher-frequency reference clock prior to switching the electronic circuit to the higher-frequency reference clock. The oscillation detection logic derives a sampled clock signal from the higher-frequency reference clock, wherein the sampled clock signal has a slower frequency than the lower-frequency reference clock. The oscillation detection logic then compares the sampled clock signal against the lower-frequency reference clock to determine the stability of the higher-frequency reference clock.

Abstract: Aspects disclosed in the detailed description include apparatuses, methods, and systems for glitch-free clock switching. In this regard, in one aspect, an electronic circuit is switched from a lower-frequency reference clock to a higher-frequency reference clock. An oscillation detection logic is configured to determine the stability of the higher-frequency reference clock prior to switching the electronic circuit to the higher-frequency reference clock. The oscillation detection logic derives a sampled clock signal from the higher-frequency reference clock, wherein the sampled clock signal has a slower frequency than the lower-frequency reference clock. The oscillation detection logic then compares the sampled clock signal against the lower-frequency reference clock to determine the stability of the higher-frequency reference clock.

Abstract: Aspects disclosed in the detailed description include high-frequency signal observations in electronic systems. In this regard, a high-frequency signal observation circuit is provided in an electronic system to enable high-frequency signal observations. In one aspect, the high-frequency signal observation circuit comprises an observation signal selection circuit. The observation signal selection circuit is programmably controlled to select an observation signal among a plurality of electronic input signals (e.g., control signals) received from the electronic system. In another aspect, the high-frequency signal observation circuit is configured to utilize a bypass data path, which is routed around serializer/deserializer (SerDes) logic in the electronic system, to output the observation signal for observation. By programmably selecting the observation signal and outputting the observation signal via the bypass data path, it is possible to examine accurately any high-frequency signal (e.g.