17.1.2 Register Write Protection

To prevent any single software error from modifying the configuration of Reset Controller (RSTC), Supply Controller (SUPC), Real-time Timer (RTT), General Purpose Backup Register (GPBR), Real-time Clock (RTC) and Dual Watchdog Timer (DWDT), some registers of these peripherals can be write-protected by setting the WPEN and/or WPITEN bits in the System Controller Write Protection Mode register (SYSC_WPMR).

Note: The DWDT embeds additional write protection mechanisms.

When write protection is enabled, any attempt to write these registers is reported in the System Controller Write Protection Status register (SYSC_WPSR).

The following registers can be write-protected when SYSC_WPMR.WPEN=1:

  • WDT 0 Control Register
  • WDT 0 Mode Register
  • WDT 0 Window Level Register
  • WDT 0 Window Interrupt Register
  • RSTC Mode Register
  • RTC Control Register
  • RTC Mode Register
  • RTC Time Alarm Register
  • RTC Calendar Alarm Register
  • RTC Tamper Control Register
  • RTT Mode Register
  • RTT Alarm Register
  • RTT Modulo Selection Register
  • GPBR Full Clear Register (Write protection only. No violation report.)
  • GPBR Registers
  • SUPC Control Register
  • SUPC Control Register
  • SUPC Supply Monitor Mode Register
  • SUPC Mode Register
  • SUPC Wakeup Mode Register
  • SUPC Wakeup Input Register
  • SUPC Extended mode Register
  • SUPC Backup Mode Register
  • WDT 1 Control Register
  • WDT 1 Mode Register
  • WDT 1 Window Level Register
  • WDT 1 Window Interrupt Register

The following registers can be write-protected when SYSC_WPMR.WPITEN=1:

  • WDT 0 Interrupt Enable Register
  • WDT 0 Interrupt Disable Register
  • RTC Interrupt Enable Register
  • RTC Interrupt Disable Register
  • SUPC Interrupt Enable Register
  • SUPC Interrupt Disable Register
  • WDT 1 Interrupt Enable Register
  • WDT 1 Interrupt Disable Register