The following section provides details
of steps involved in re-configuring the PLL with new frequency:
- Switch all the peripheral
clocks which are derived from PLL to WUCPU_CLK (XTAL_CLK) so that when PLL
is unlocked other peripheral are in safe state. (Refer to the IP Clock
Configurations section for programming.)
- Change the CPU clock source
to WUCPU_CLK (XTAL_CLK) by programming the R5SS GCM with the value of 0x0
and SYS_CLK GCD (optional) with the value of 0x0 so that CPU does not enter
into dead lock condition. (Refer to the Root
Clock Configurations for programming.)
- Assert the TINTZ signal of
the PLL to reset the internal FSM of PLL, TOP_RCM.PLL_CORE_CLKCTRL.TINTZ =
0x0.
- Follow the steps mentioned in
Sequence to Configure the CORE PLL from point 3 to 12 to
re-configure the PLL CORE.
Note: Follow the
above-mentioned steps except point (2) to re-configure the PLL
PER.