1.3 Microcontroller Monitoring

The Class B Functional Safety libraries ensure the microcontroller operates correctly. These libraries are free to use and a part of MPLAB® Code Configurator (MCC). MCC is a graphical tool used to configure the hardware peripherals on the microcontroller.

Warning: This example is not certified for functional safety. It is intended to illustrate the usage of the Class B libraries, but a detailed failure mode analysis is required before utilizing this circuit in an application.

The Class B libraries are designed for IEC 60730. This application implements the following tests from the Class B libraries to improve failure mode coverage:

  • CPU
    • Verifies the CPU registers are operating as expected
  • Flash
    • Scans the program Flash and verifies the memory has not been corrupted
  • SRAM
    • Runs a Checkboard (or March) test pattern through the memory to verify the SRAM cells are functioning correctly
  • Stack
    • Periodically tests the hardware stack to make sure it is operating correctly
  • Watchdog Timer
    • Tests the Watchdog Timer (WDT) on start-up to make sure the hardware module is working properly
Important: The SRAM test is only recommended with level S compiler optimizations.