SPRUJF2A March 2026 – March 2026 AM13E23019
In watchdog mode, the WWDT is configured to count up to the specified WWDT period determined by the CLKDIV and PER bits of the WWDTCTL0 register (see WWDT Period Timing Options). The WWDT period consists of a closed window span and an open window span. The WWDT counter must be restarted with the configured open window of the WWDT period, or the WWDT will assert a WWDT violation to SYSCTL and a reset will be generated.
The window watchdog timer supports detecting both a "too late" response as well as a "too early" response through the use of the closed window, as shown in Watchdog Functionality. The closed window span begins first, followed by the open window span. The WWDT can only be restarted during the open window span. Restarting the WWDT during the open window span restarts the WWDT counter and the closed window span begins again. Any attempt to restart the WWDT during the closed window span results in a violation. Following the closed window, if the WWDT is not restarted before the end of the open window, the WWDT period expires and a WWDT violation is generated.
If the closed window functionality is not desired, it can be disabled by setting the closed window span to 0%, giving traditional watchdog timer functionality where the WWDT can be reset any time before the WWDT period expires.