Hardware safety mechanisms only work if the software running alongside them behaves the way the safety case assumes it will, this is the core concern of ISO 26262 Part 6.
Freedom From Interference (FFI): the techniques that let a safety-critical function (say, an ASIL D contactor control routine) share a microcontroller with non-safety code such as a machine-learning-based state-of-charge estimator, typically enforced through Memory Protection Unit (MPU) partitioning and OS-level timing protection.
This also covers the coding side of Part 6: MISRA C:2012 compliance, static analysis and structural coverage targets (statement, branch, and MC/DC). Along with the runtime safety mechanisms expected of safety-rated firmware, including:
- program flow monitoring via challenge-response watchdogs
- stack overflow checks
- CRC verification of safety-relevant memory
References
- Freedom From Interference in Embedded Software, UL Solutions
- Safety Mechanisms & Diagnostics, ISO 26262 Academy
- Code Coverage: ISO 26262 Software Compliance, Parasoft
See also: Software Development and Functional Safety, BMS Hardware Safety Mechanisms, Safety Case & Verification