TS-4900 Watchdog
The CPU's watchdog timer is a hardware component that helps ensure the stability and responsiveness of the system. It does this by resetting the system if it detects that a certain process or application is not functioning as expected. If the watchdog timer is not regularly reset or "fed," it will expire and trigger a system reset.
By default, the watchdog timer has a timeout period of 60 seconds. However, it is powered by a ring oscillator that may not be perfectly accurate, meaning the timer may expire more quickly than expected. To ensure that the watchdog timer does not expire prematurely, it should be reset or "fed" at least 4 times more frequently than its configured timeout period. For example, if the timeout is set to 60 seconds, the watchdog should be reset at least every 15 seconds.
The kernel provides an interface to the watchdog driver at /dev/watchdog. This interface can be used to enable the watchdog timer by feeding it from an application. For more information on using the watchdog timer, refer to the kernel documentation at the following links: