25.1 Description

The Reinforced Safety Watchdog Timer (RSWDT) works in parallel with the Watchdog Timer (WDT) to reinforce safe watchdog operations.

The RSWDT can be used to reinforce the safety level provided by the WDT in order to prevent system lock-up if the software becomes trapped in a deadlock. The RSWDT works in a fully operable mode, independent of the WDT. The RSWDT clock source is automatically selected from either the Slow RC oscillator clock, or from the Main RC oscillator divided clock to get an equivalent Slow RC oscillator clock. If the WDT clock source (for example, the 32 kHz crystal oscillator) fails, the system lock-up is no longer monitored by the WDT because the RSWDT performs the monitoring. Thus, there is no lack of safety regardless of the external operating conditions. The RSWDT shares the same features as the WDT (i.e., a 12-bit down counter that allows a watchdog period of up to 16 seconds with slow clock at 32.768 kHz). It can generate a general reset or a processor reset only. In addition, it can be stopped while the processor is in Debug mode or Idle mode.