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Industrial Safety Self-Test Library

IEC 61508 is an international standard for functional safety of Electrical, Electronic, and Programmable Electronic (E/E/PE) systems. It defines functional safety as part of the overall safety relating to an Equipment Under Control (EUC) or system. The EUC can be as simple as a switch or as complex as a Programmable Logic Controller (PLC). IEC 61508 encompasses four different Safety Integrity Levels (SILs), with SIL 1 having the lowest level and SIL 4 having the highest level of safety in E/E/PE systems.

We offer an SIL Self-Test Library (STL) for our 32-bit microcontrollers (MCUs) that was developed with our partner, embeX GmbH. This library is certified up to SIL 2 for a single MCU or single channel. The STL is part of an overall safety package that also includes a Safety Manual as well as a Safety Checklist to provide you with a solid foundation on which to build a system certified to the IEC 61508 Industrial Safety Standard.

Achieving Higher Safety Levels

For many functional safety applications, redundancy or a dual-channel solution can be created for implementing a higher safety level for SIL 3. For example, two MCUs using the SIL 2 STL can be used to achieve SIL 3 in an overall system.

The SIL 2/3 STL provides the following advantages:

  • Application independent for use in any simple to complex design
  • Certification by TÜV Rhineland, a recognized certification body
  • Compiler-independent object code for design flexibility
  • Software-based library to detect random hardware failures in the Arm® Cortex® M0+ core, Flash memory and SRAM
  • Diagnostic tests that are executed at startup and at run-time
  • Fault insertion tests to verify operation of the self-test diagnostic routines
  • Thoroughly tested diagnostic functions based on the device‘s architecture and available features to reduce development time
  • Reduced time and costs in certifying the end system/application


SIL 2/3 STL Licensing and Evaluation

The SIL 2/3 STL is available as an evaluation license with a development kit or as a full production license for the SAM D21 and SAM L21 safety-enabled devices. These devices have a  “-SLL” suffix at the end of the part number, for example: ATSAMD21J18A-AU-SLL. To request additional information, please fill out and submit the request form.

Components Covered by the SIL 2/3 STL

The following elements are tested by the Self-Test Library with a Diagnostic Coverage (DC) of ≥ 90%:

  • Program Memory (ROM)
  • Data Memory (RAM)
  • RAM Address Lines
  • Stack
  • Core-Register
  • OpCodes
  • Special Function Register (SFR)

32-Bit Industrial Safety SIL Microcontrollers

More SAM D21 and SAM L21 devices can be added to the SIL 2/3 STL in addition to the base devices listed below and in the datasheet. Please contact your local Microchip Sales Office or use the form above to submit your request to have devices added.