SM CODE
SDIO_SM_2
Multiple-fault protection
CPU_SM_0: Periodic core self-test software
Recommendations and known limitations
To give an example on checksum encoding capability, using just a bit-by-bit addition is
unappropriated.
This safety mechanism can overlap with information redundancy techniques implemented at
system level to address failure of physical device connected to SDIO/SMMMC port.
Note:
The safety mechanisms mentioned above are addressing the SDIO/SMMC interface included in STM32 MCUs.
No claims are done in this Safety Manual about the mitigation of hardware random faults affecting the external
memory connected to SDIO/SMMC port.
3.6.40
Controller area network (bxCAN)
Table 142.
CAN_SM_0
SM CODE
CAN_SM_0
Description
Periodic read-back of configuration registers
Ownership
End user
Detailed implementation
This method must be applied to bxCAN configuration registers.
Detailed information on the implementation of this method can be found in
Section 3.6.14 Extended interrupt and events controller (EXTI)
.
Error reporting
Refer to NVIC_SM_0
Fault detection time
Refer to NVIC_SM_0
Addressed fault model
Refer to NVIC_SM_0
Dependency on
Device
configuration
Refer to NVIC_SM_0
Initialization
Refer to NVIC_SM_0
Periodicity
Refer to NVIC_SM_0
Test for the diagnostic
Refer to NVIC_SM_0
Multiple-fault protection
Refer to NVIC_SM_0
Recommendations and known limitations
Refer to NVIC_SM_0
Table 143.
CAN_SM_1
SM CODE
CAN_SM_1
Description
Protocol error signals
Ownership
ST
Detailed implementation
CAN communication module embeds protocol error checks (like error counters) conceived to
detect network-related abnormal conditions. These mechanisms are able anyway to detect a
marginal percentage of hardware random failures affecting the module itself.
Error signals connected to these checkers are normally handled in a standard communication
software, so the overhead is reduced.
Error reporting
Several error condition are reported by flag bits in related CAN registers.
Fault detection time
Depends on peripheral configuration (for example baud rate). Refer to functional
documentation.
Addressed fault model
Permanent/transient
Dependency on
Device
configuration
None
Initialization
Depends on implementation
Periodicity
Continuous
UM2305
Hardware and software diagnostics
UM2305
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Rev 10
page 79/110
