Independent Watchdog (Iwdg), System Window Watchdog (Wwdg); Table 89. Wdg_Sm_0; Table 90. Wdg_Sm_1 - ST STM32F2 Series User Manual

3.6.20

Independent watchdog (IWDG), system window watchdog (WWDG)

SM CODE
Description
Ownership
Detailed implementation
Error reporting
Fault detection time
Addressed fault model
Dependency on MCU configuration
Initialization
Periodicity
Test for the diagnostic
Multiple faults protection
Recommendations and known limitations
SM CODE
Description
Ownership
Detailed implementation
Error reporting
Fault detection time
Addressed fault model
Dependency on MCU configuration
Initialization
Periodicity
Test for the diagnostic
Multiple faults protection
Recommendations and known
limitations
UM1845 - Rev 4
Table 89. WDG_SM_0
WDG_SM_0
Periodical read-back of configuration registers
End user
This method must be applied to WDG or WDG configuration registers.
Detailed information on the implementation of this method can be found in
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Refer to NVIC_SM_0
Table 90. WDG_SM_1
WDG_SM_1
Software test for watchdog at startup
End user
This safety mechanism ensures the right functionality of the internal watchdogs in use. At startup, the
software test programs the watchdog with the required expiration timeout, stores a specific non-trivial
code in SRAM and waits for the reset signal. After the watchdog reset, the software understands that
the watchdog has correctly triggered, and does not execute the procedure again
Depends on implementation
Depends on implementation
Permanent
None
Depends on implementation
Startup (see below)
Not needed
CPU_SM_0: periodical core self-test software
In a typical end user application, this test can be executed only at startup and during maintenance or
offline periods. It could be associated to IEC61508 concept of "proof test" and so it cannot be
accounted for a diagnostic coverage contribution during operating time.
Description of hardware and software diagnostics
UM1845
Section 3.6.5
page 61/108