18.3.14 Configuration Change Protection (CCP)

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

Attempting to write to a protected register without following the appropriate CCP unlock sequence leaves it unchanged.

The following registers are under CCP:

Table 18-4. CLKCTRL - Registers Under Configuration Change Protection
RegisterKey
CLKCTRL.MCLKCTRLAIOREG
CLKCTRL.MCLKCTRLBIOREG
CLKCTRL.MCLKCTRLCIOREG
CLKCTRL.MCLKINTCTRLIOREG
CLKCTRL.MCLKINTFLAGSIOREG
CLKCTRL.MCLKTIMEBASEIOREG
CLKCTRL.MCLKCFD0CTRLAIOREG
CLKCTRL.MCLKCFD1CTRLAIOREG
CLKCTRL.MCLKCFM0CTRLAIOREG
CLKCTRL.MCLKCFM0CTRLBIOREG
CLKCTRL.MCLKCFM1CTRLAIOREG
CLKCTRL.MCLKCFM1CTRLBIOREG
CLKCTRL.OSCHFCTRLAIOREG
CLKCTRL.PLLCTRLAIOREG
CLKCTRL.OSC32KCTRLAIOREG
CLKCTRL.XOSC32KCTRLAIOREG
CLKCTRL.XOSCHFCTRLAIOREG