ST STM32L4 Series User Manual

SM CODE BUS_SM_0
Detailed implementation
The intra-chip connection resources (Bus Matrix, AHB or APB bridges) needs to be
periodically tested for permanent faults detection. Note that STM32L4 and STM32L4+
Series devices have no hardware safety mechanism to protect these structures. The test
executes a connectivity test of these shared resources, including the testing of the arbitration
mechanisms between peripherals.
According to IEC 61508:2 Table A.8, A.7.4 the method is considered able to achieve high
levels of coverage.
Error reporting Depends on implementation
Fault detection time Depends on implementation
Addressed fault model Permanent
Dependency on Device configuration None
Initialization Depends on implementation
Periodicity Periodic
Test for the diagnostic Not applicable
Multiple-fault protection CPU_SM_0: Periodic core self-test software
Recommendations and known limitations
Implementation can be considered in large part as overlapping with the widely used Periodic
read-back of configuration registers required for several peripherals.
Table 15. BUS_SM_1
SM CODE BUS_SM_1
Description Information redundancy in intra-chip data exchanges
Ownership End user
Detailed implementation
This method requires to add some kind of redundancy (for example a CRC checksum at
packet level) to each data message exchanged inside Device.
Message integrity is verified using the checksum by Application software, before consuming
data.
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
Implementation can be in large part overlapping with other safety mechanisms requiring
information redundancy on data messages for communication peripherals. Optimizations are
therefore possible.
3.6.3 Embedded SRAM
Table 16. RAM_SM_0
SM CODE RAM_SM_0
Description Periodic software test for static random access memory (SRAM)
Ownership End user or ST
UM2305
Hardware and software diagnostics
UM2305 - Rev 10
page 17/110

ST STM32L4 Series Specifications

General

Brand	ST
Model	STM32L4 Series
Category	Microcontrollers
Language	English