STMicroelectronics AN3307 Guidelines for IEC60335 Class B Certification in STM32F1xx Applications

About this manual

The document outlines the requirements for ensuring electronic appliance safety under IEC 60335-1 standards, specifically focusing on Class B compliance where software must prevent unsafe operation following component failures. It details how the STM32F1xx family of microcontrollers can be utilized to meet these rigorous safety criteria through specific hardware and software techniques.

The text describes a dedicated software package designed for integration into user applications. This solution includes generic tests for micro-specific components such as CPU registers, clock systems, memory integrity, and watchdogs. It also covers application-specific areas like interrupt handling and I/O control to ensure the appliance remains safe even if the microcontroller fails or is reset.

What's inside

• Compliance with IEC and VDE standards
• Generic tests included in firmware library
• Application-specific tests not included in library
• Class B software package principles
• Package organization and projects
• Startup self-tests description
• Periodic runtime self-test initialization
• Description of periodic runtime self-tests

Specifications

Frequently asked questions

What is the difference between Class A, B, and C appliances?

Class A relies on hardware safety; Class B uses software to prevent unsafe operation after a failure; Class C uses software for special hazards.

Which microcontroller parts must be tested for Class B compliance?

Micro-specific parts include CPU registers, clock, and memory; application-specific parts include interrupts and I/O peripherals.

Is the Class B software package available for free download?

No, the associated firmware package is available upon request only from local ST sales offices.