25.6.10.1 Security Bit Set Procedure

The Security Bit Set procedure is as follows:

  1. Issue the Set Security Bit (SSB) command. If a debugger is connected, it still has access to the device after issuing this command (DSU STATUSB.PROT = 0).
  2. Check NVMNCTRL.INTFLAG.PROGE and NVMNCTRL.INTFLAG.DONE.
  3. Reset the NVMCTRL peripheral or the device.
  4. After reset, DSU STATUSB.PROT = 1.

To reflect the NVM security bit state correctly, the NVMCTRL needs to replay the start-up procedure. This is done by issuing a SWRST command or by resetting the device.