4.16.6 PLL Controls

The PMC embeds 4 PLLs that are controlled by the PMC_PLL_CTRL0, PMC_PLL_CTRL1, PMC_PLL_SSR, PMC_PLL_ACR and PMC_PLL_UPDATE registers. Each PLL is accessed in read or write through its index as defined in the table below, corresponding to the register field PMC_PLL_UPDT.ID. At any time, PLL_CTRL0, PLL_CTRL1 and PLL_ACR reflect the controls for the PLL with index PMC_PLL_UPDT.ID. When the UPDATE bit is set in PMC_PLL_UPDT, the PLL of index PMC_PLL_UPDT.ID is updated with the content of registers PLL_CTRL0, PLL_CTRL1 and PLL_ACR.

Each PLL is fed by either the MAINCK or the main crystal oscillator and has a constraint on the frequency it can generate on its clock output. Refer to the section “Electrical Characteristics”.

The table below describes all PLLs with their names and source clocks. For maximum frequency, refer to the section “Electrical Characteristics”.

Table 4-7. PLL IDs
Index	PLL Name	Clock Name	PLL Clock Source	Usage Example
0	PLLA	PLLACK	MAINCK	CPU_CLK and MCK clock sources
1	UPLL	ULLCK	MAIN XTAL OSC	UTMI clock source
2	AUDIOPLL	AUDIOPLLCK	MAIN XTAL OSC	AUDIOCLK output clock source
3	LVDSPLL	LVDSPLLCK	MAIN XTAL OSC	LVDS clock source
4	PLLADIV2	PLLADIV2CK	MAINCK	Generic clocks source