SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
A normally configured timer supports a software watchdog capability in which software can continually reset the timer by writing to the SCTM_CTCR_j[1] RESET bit or to the corresponding bit in the SCTM_CTGRST0 register before the interval expires (and the interrupt is generated).
The timers also support a hardware watchdog function where selected input events can start and reset the timers without software interaction.
When hardware watchdog mode is enabled, the SCTM_CTCR_WT/WOT_j[23:16] INPSEL bit field selects the event that starts a WD timer. Once the input event is selected, the timer increments using the functional clock. If it reaches the interval match value before being reset, the interrupt is generated.
The WD timer is reset when an input event is detected. This resets the counter to 0. The counter does not restart until another input event is detected. The state-machine shown in Figure 8-22 illustrated the functional operation of the timer when configured for hardware watchdog mode.
Some important notes about WD timer mode operation: