22.3.10 Protecting Register Contents

Any attempted write to the Timeout Value (ERRCTRL.TIMEOUT), Error Source Control x (ERRCTRL.ESCx), or Error Status Flag Test Injection (ERRCTRL.ESFTEST) registers when not in the CONFIG state will be discarded and return a Bus Error response on the data bus.

Transition to CONFIG is only allowed from the NORMAL state by writing to the ERRCTRL State (STATE) bit field in the Control A (ERRCTRL.CTRLA) register. An attempted transition from any other state will be discarded and return a Bus Error.

Attempted writes to a CCP-protected register outside of the CCP sequence will be discarded and return a Bus Error response on the data bus. A CCP sequence protects the following registers:
  • ERRCTRL.CTRLA
  • ERRCTRL.ESFTEST