SPRUJ79 November 2024 F29H850TU
The PLL is responsible for synthesizing an output frequency from the input clock (from the oscillator). Figure 3-8 shows a simple block diagram of the PLL. The PLL divides the reference input for a lower frequency input into the PLL by (REFDIV + 1). Then multiplies this internal frequency by IMULT to get the VCO output clock. The PLL output is divided by (ODIV + 1) to generate PLLRAWCLK that is further divided by SYSCLKDIVSEL.PLLSYSCLKDIV to generate PLLSYSCLK.
There is PLL also called as SYSPLL and the equations shown in Figure 3-8 can be used to configure the respective PLL.
For the permissible values of the multipliers and dividers, see the documentation for their respective registers.
Many combinations of multiplier and divider can produce the same output frequency. However, the product of the reference clock frequency and the multiplier (known as the VCO frequency) must be in the range specified in the data sheet.
The clock source and PLL configuration can only be done by CPU1 and can be read by other CPUs.