SFFS779 December 2024 TMS320F28P550SJ
External watchdog helps to reduce common mode failures, as external watchdog utilizes clock, reset, and power that are separate from the system being monitored. Error response, diagnostic testability, and any necessary software requirements are defined by the external watchdog selected by the system integrator.
Texas Instruments highly recommends the use of an external watchdog in addition to the internally provided watchdogs. An internal or external watchdog can provide indication of an inadvertent activation of logic that results in an impact to safety-critical execution. Any watchdog added externally must include a combination of temporal and logical monitoring of program sequence [IEC61508-7, clause A.9.3] or other appropriate methods so that high diagnostic effectiveness can be claimed.