The IEC 60730-1 and IEC 60335-1 safety standards define the test and the diagnostic methods, effective to detect random hardware failures, that ensure the safe operation of hardware and software embedded in household appliances under the control of electronic programmable devices.
With its X-CUBE-CLASSB functional safety package based on robust built-in STM32 safety features, STMicroelectronics provides a comprehensive set of certified software self-test libraries and documentation for manufacturers to reduce significantly the development efforts, time, and cost to achieve the UL/CSA/IEC 60335-1 and the 60730-1 worldwide safety certifications for their STM32-based applications up to Class B level.
A set of test APIs focused on generic safety-critical core components (CPU, SRAM, flash memory, and clock system) is provided exclusively in the firmware package. The associated examples suggest a possible integration of this set in a final application where simple code demonstrates sequential polling of the APIs and checking results of the performed partial tests.
Only the testing methods applied are the subject of the certification. The API integration provided, the extensions to the test of other application-specific core components, and the necessary configuration of all associated hardware through HAL drivers (if applied) are inspected but not certified for safety. This is supposed to be subject to further modification, extension, and verification entirely under the end-user's responsibility (such as the replacement of HAL drivers with sequences calling LL drivers directly).
The parts of the library and examples of its integration, which are delivered as full source code, can lead to dependence on the compilers and HAL driver versions available at the time of the certification process. Users must consider this point when combining the certified API sources with their latest versions as described in the associated user manual.
The X-CUBE-CLASSB functional safety package consists of a set of expansion software for STM32Cube (self-test libraries and their integration examples) and a dedicated user guide. The user guide is either the application note Guidelines for obtaining UL/CSA/IEC 60730-1/60335-1 Class B certification in any STM32 application (AN4435) or the user manual STM32U5 Series IEC 60730 self-test library user guide (UM2986). The "Ordering information" of the X-CUBE-CLASSB data brief provides a summary of the versions available.
Common safety principles described in the microcontroller series safety manuals, available with the X-CUBE-STL industrial safety package, are mostly applicable as well, despite the fact that these manuals target different industry-oriented standards. This is due to the significant overlay between these safety standards.