7.4.12 CPU Registers Under Configuration Change Protection

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

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

The following registers are under CCP:

Table 7-3. CPU - Registers under Configuration Change Protection
Register	Key
CPU.CTRLA	IOREG
CPU.INTFLAGS	IOREG

DS40002684A

The online versions of the documents are provided as a courtesy. Verify all content and data in the device’s PDF documentation found on the device product page.