ST STM32L4 Series User Manual

Table 109. ATIM_SM_2
SM CODE ATIM_SM_2
Description 1oo2 for input capture timers
Ownership End user
Detailed implementation
This method is conceived to protect timers used for acquisition and measurement of external
signals (input capture, encoder reading). The implementation consists in connecting the
external signals also to a redundant timer, and checking the coherence of the measured data
at application level.
Coherence check between timers is executed each time the reading is used by Application
software.
Error reporting Depends on implementation
Fault detection time Depends on implementation
Addressed fault model Permanent/transient
Dependency on Device configuration None
Initialization Depends on implementation
Periodicity On demand
Test for the diagnostic Not applicable
Multiple-fault protection CPU_SM_0: Periodic core self-test software
Recommendations and known limitations
To reduce the potential effect of common cause failures, it is suggested to use for redundant
check a channel belonging to a different timer module and mapped to non-adjacent pin on the
device package.
Table 110. ATIM_SM_3
SM CODE ATIM_SM_3
Description Loopback scheme for pulse width modulation (PWM) outputs
Ownership End user
Detailed implementation
This method is implemented by connecting the PWM to a separate timer channel to acquire
the generated waveform characteristics.
The guidelines are the following:
• Both PWM frequency and duty cycle are measured and checked versus the expected
value.
• To reduce the potential effect of common cause failure, it is suggested to use for
the loopback check a channel belonging to a different timer module and mapped to
non-adjacent pins on the device package.
This measure can be replaced under the end-user responsibility by different loopback
schemes already in place in the final application and rated as equivalent. For example if
the PWM is used to drive an external power load, the reading of the on-line current value can
be used instead of the PWM duty cycle measurement.
Error reporting Depends on implementation
Fault detection time Depends on implementation
Addressed fault model Depends on implementation
Dependency on Device configuration None
Initialization Depends on implementation
Periodicity Continuous
Test for the diagnostic Not applicable
Multiple-fault protection CPU_SM_0: Periodic core self-test software
UM2305
Hardware and software diagnostics
UM2305 - Rev 10
page 63/110

ST STM32L4 Series Specifications

General

Brand	ST
Model	STM32L4 Series
Category	Microcontrollers
Language	English