SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
The USB3_PHY component receives a feedback clock, PIPE_MCLK, which is the reflected version of the PIPE_PCLK (PIPE port synchronizing clock) generated by the USB3_PHY component. The clock is turned on/off according to the PIPE power-down port states. As PIPE port works in source-synchronous mode, all data movement from the MAC layer to the PIPE interface is synchronous to PIPE_PCLK.
The USB3_PHY.PLL_CLK high-speed transmission (2.5 GHz) clock input pin is connected to the DPLL_USB_OTG_SS clock output, CLKDCOLDO. For more information on the DPLL_USB_OTG_SS.CLKDCOLDO output clock settings, see Section 26.2.4.3.4.2, USB3_PHY DPLL Output Clock Configuration.
As shown in Figure 26-11, the same PRCM-sourced clock (USB_OTG_SS_REF_CLK), tied at the USB3_PHY subsystem REF_CLK input, supplies the USB3_PHY RX/TX components and the DPLL_USB_OTG_SS.CLKINP inputs.
The PHY associated power sequencer receives PRCM.USB_OTG_SS_REF_CLK as a functional clock . Software must notify the PHY logic about which REF_CLK frequency is selected by writing the CTRL_CORE_PHY_POWER_USB[31:22] USB_PWRCTL_CLK_FREQ bit field, as follows:
The USB3PHY_LFPS_CLK clock input is used to support different USB3_PHY functions, such as the low-frequency periodic signaling (LFPS) generator. This USB3_PHY_TX clock input is tied to the PRCM.CORE_USB_OTG_SS_LFPS_TX_CLK functional clock.
The USB3_PHY_RX deserializer I/O wake-up logic is supported by the PRCM.COREAON_32K_GFCLK clock, applied at the USB3PHY_WKUP_CLK input.