SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Only the DPLL_USB_OTG_SS output, CLKDCOLDO, is used to provide the high-speed clock at the PLL_CLK pin of the USB3_PHY. Only the REGM, REGN, and SD divider values are used within the DPLL clock generator subsystem to adjust the CLKDCOLDO output clock frequency. This is done through programming the DPLLCTRL_USB_OTG_SS.DPLLCTRL_USB_OTG_SS.PLL_CONFIGURATION1[20:9], PLL_REGM, DPLLCTRL_USB_OTG_SS.PLL_CONFIGURATION1[8:1], PLL_REGN, and DPLLCTRL_USB_OTG_SS.PLL_CONFIGURATION3[17:10] PLL_SD bit fields, respectively. The USB3_PHY DPLL CLKOUT and CLKOUTLDO outputs are not used, and internal REGM2 and REGM1 dividers are not software controllable.
At DPLL/DPLLCTRL integration level the PLL_REGM1[3:0] and PLL_REGM2[6:0] divider control signals are hardware tie-off to 0x0 and 0x1, respectively.
For more details on output clock settings sequence, see Section 26.2.4.3.7.3, USB3_PHY DPLL Clock Programming Sequence.