Table 61. Adc_Sm_3 - ST STM32F2 Series User Manual

SM CODE
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
ADC_SM_2
The guidelines for the implementation of the method are the following:
• The expected range of the data to be acquired are investigated and adequately documented. Note
that in a well-designed application it is improbable that during normal operation an input signal has a
very near or over the upper and lower rail limit (saturation in signal acquisition).
• If the application software is aware of the state of the system, this information is to be used in the
range check implementation. For example, if the ADC value is the measurement of a current through a
power load, reading an abnormal value such as a current flowing in opposite direction versus the load
supply may indicate a fault in the acquisition module.
• As the ADC module is shared between different possible external sources, the combination of
plausibility checks on the different signals acquired can help to cover the whole input range in a very
efficient way
Depends on implementation
Depends on implementation
Permanent and Transient
None
Depends on implementation
Continuous
Not needed
CPU_SM_0: periodical core self-test software
The implementation (and the related diagnostic efficiency) of this safety mechanism are strongly application-
dependent
Table 61.
ADC_SM_3
Periodical software test for ADC
End user
The method is implemented acquiring multiple signals and comparing the read value with the
expected one, supposed to be know. Method can be implemented with different level of complexity:
• Basic complexity: acquisition and check of upper or lower rails (VDD or VSS) and internal
reference voltage
• High complexity: in addition to basic complexity tests, acquisition of a DAC output connected
to ADC input and checking all voltage excursion and linearity
Depends on implementation
Depends on implementation
Permanent
None
Depends on implementation
Periodic
Not needed
CPU_SM_0: periodical core self-test software
Combination of two different complexity method can be used to better optimize test frequency in
high demand safety functions
Description of hardware and software diagnostics
ADC_SM_3
UM1845
page 45/108