11.3.5 Configuration Change Protection

This peripheral has registers that are under Configuration Change Protection (CCP). In order to write to these, a certain key must be written to the CPU.CCP register first, followed by a write access to the protected bits within four CPU instructions.

It is possible to try writing to these registers at any time, but the values are not altered.

The following registers are under CCP:

Table 11-2. CLKCTRL - Registers Under Configuration Change Protection
RegisterKey
CLKCTRL.MCLKCTRLBIOREG
CLKCTRL.MCLKLOCKIOREG
CLKCTRL.XOSC32KCTRLAIOREG
CLKCTRL.MCLKCTRLAIOREG
CLKCTRL.OSC20MCTRLAIOREG
CLKCTRL.OSC20MCALIBAIOREG
CLKCTRL.OSC20MCALIBBIOREG
CLKCTRL.OSC32KCTRLAIOREG