10.3.6 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.
Attempting to write to a protected register without following the appropriate CCP unlock sequence leaves the protected register unchanged.
The following registers are under CCP:
Register | Key |
---|---|
NVMCTRL.CTRLA | SPM |