The DPLL_HDMI generates the clocks to the HDMI_PHY module and the DPLL_HDMI_CLK1 clock used by the DISPC and various system modules.
The DPLL_HDMI factors must be calculated based on the required input and output frequencies, keeping the DPLL_HDMI internal reference frequency in the appropriate range:
Figure 11-20 shows the programming sequence.
Table 11-13 summarizes the registers for the DPLL_HDMI programming sequence.
Table 11-13 DPLL_HDMI Register Call Summary for HDMI PLL Programming Sequence Note: The following should be considered for the programming sequence in Figure 11-20:
- The equation for the DPLL output applies to both CLKDCOLDO and CLKOUTLDO outputs of the DPLL_HDMI. The REGM2 divisor value must be considered only in case the CLKOUTLDO frequency needs to be calculated. Programming of REGM.f is needed only if fractional M divider is required by the use case.
- The DPLL_HDMI_CLK1 clock is sourced from the CLKDCOLDO output of the DPLL_HDMI:
- The DPLL_HDMI_CLK1 frequency must be a multiple of the PCLK frequency (for proper settings of the PCD and LCD factors in the DISPC).
- The DPLL_HDMI_CLK1 frequency must be lower than 186 MHz.
- The PLLCTRL_HDMI_CONFIGURATION2[3:1] PLL_SELFREQDCO register bit field should be programmed depending on the value of CLKDCOLDO = CLKINP × M/(N + 1). See Section 11.1.3.4.3, DPLL_HDMI Operations.
- Programming of other DPLL_HDMI parameters is available for software flexibility, but it is not recommended to update their values in normal use. For the recommended DPLL_HDMI values, see Section 11.1.3.4.10, DPLL_HDMI Recommended Values.