23.6.3 Two-Way Lock and Unlock

Each module that uses the system lock feature describes register bits and functions, which are affected by this system lock feature. A specific sequence of writes to the SYSKEY register unlock the access to those register bits and features.

This locking method provides a two-way (locking and unlocking) write lock of system-critical registers. It includes protection for the following registers:

  • CRU.OSCCON
  • CRU.OSCTRM
  • CRU.SPLLCON
  • CRU.RSWRST
  • CRU.RNMICON
  • CRU.PB1DIV
  • CRU.PB2DIV
  • CRU.PB3DIV
  • CRU.PB4DIV
  • CRU.SLEWCON
  • CRU.CLK_DIAG