31.12 Programmable Clock Output Controller

The PMC controls three signals to be output on the external pins PCKx. Each signal can be independently programmed via the Programmable Clock registers (PMC_PCKx).

PCKx can be independently selected between SLCK, MAINCK, PLLACK, UPLLCKDIV and MCK by configuring PMC_PCKx.CSS. Each output signal can also be divided by 1 to 256 by configuring PMC_PCKx.PRES.

Each output signal can be enabled and disabled by writing a ‘1’ to the corresponding bits PMC_SCER.PCKx and PMC_SCDR.PCKx, respectively. The status of the active programmable output clocks is given in PMC_SCSR.PCKx.

The status flag PMC_SR.PCKRDYx indicates that PCKx is actually what has been programmed in registers PMC_PCKx.

As the Programmable Clock Controller does not manage with glitch prevention when switching clocks, it is strongly recommended to disable PCKx before any configuration change and to re-enable it after the change is performed.