Table 78. Rtc_Sm_2; Table 79. Rtc_Sm_3 - ST STM32F2 Series User Manual

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 78. RTC_SM_2
RTC_SM_2
Information redundancy on backup registers
End user
Data stored in RTC backup registers must be protected by a checksum with encoding capability (for
instance, CRC). Checksum must be checked by application software before consuming stored
data.
This method guarantees data versus erases due to backup battery failures
Depends on implementation
Depends on implementation
Permanent and Transient
None
Depends on implementation
On demand
Not needed
CPU_SM_0: periodical core self-test software
Implementation of this safety method shows a partial overlap with an already foreseen method for
®
Cortex -M3 (CPU_SM_1); optimizations in implementing both methods are therefore possible
Table 79. RTC_SM_3
RTC_SM_3
Application-level measures to detect failures in timestamps/event capture
End user
This method must detect failures affecting the RTC capability to correct execute the timestamps/
event capture functions. Due to the nature strictly application-dependent of this solution, no detailed
guidelines for its implementation are given here
Depends on implementation
Depends on implementation
Permanent and Transient
None
Depends on implementation
Periodic/On demand
Not needed
CPU_SM_0: Periodical core self-test software
This method must be used only if the timestamps/event capture function is used in the safety function
implementation. It is worth to note that the use of timestamp/event capture in safety related
applications where the MCU is in sleep or stop mode is prevented by the assumed requirement
ASR7 (refer to Section 3.3.1 )
Description of hardware and software diagnostics
UM1845
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