SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
VIDEO1 PLL and VIDEO2 PLL use type-A instances of the DPLL modules. For information regarding DPLL types, see Power, Reset, and Clock Management.
Figure 11-10 shows the internal reference diagram of a single VIDEO PLL.
Reference clock control is enabled with PLL_CONFIGURATION2[13] PLL_REFEN bit.
Figure 11-11 is a simplified block diagram of the DPLL_VIDEO instance used for pixel clock generation.
The input clock CLKINP goes to a pre-divider N + 1.The entire loop runs on the REFCLK clock after this pre-divider. The value of N + 1 is controlled through the PLL_CONFIGURATION1[8:1] PLL_REGN bit field. The CLKINP range is 0.032MHz to 52MHz. The REFCLK range is 0.15MHz to 52MHz.
The output clock DCOCLK is synthesized by a digitally controlled oscillator (the DCO block) that automatically detects the frequency range. The DCOCLK frequency can be given with DCOCLK = CLKINP × 2 × M / (N + 1). For that purpose the feedback multiplier M must be configured through the PLL_CONFIGURATION1[20:9] PLL_REGM bit field.
The CLKOUT frequency can be given with CLKOUT = DCOCLK / (M2 × 2) = DCOCLK / 62. The M2 divider value is hardcoded in HW at 31 (0x1F).
DPLL_VIDEO1 supports Spread Spectrum Clocking (SSC) using the configurations described in the device Spread Spectrum Clocking Configuration Application Report (SPRABY0). The SSC feature on DPLL_VIDEO2 is not supported.