Does every single part of the hardware element in an ISO 26262 compliant system have to be developed according to ISO 26262? Not necessarily!
Hardware component qualification is an alternative means of compliance with ISO 26262-5. Every safety-related hardware component and part used within the scope of ISO 26262 is subject to standard qualification.
In terms of hardware qualification, hardware components can be classified into three categories: basic part, intermediate part or component, and complex component. A brief description of these three categories can be found below:
- Basic part: Hardware parts, which can be categorized as a passive component or discrete semiconductors, can be classified as a basic part. Standard qualification is sufficient for basic parts. The standard does not require such parts to be developed accordingly. For example, Resistors and Diodes.
- Intermediate parts or components: Hardware parts, or components which provide a dedicated functionality to the system, can be classified as an intermediate part or component. Depending on the level, these are integrated and tested in accordance with ISO 26262-4 or ISO 26262-5, or both in addition to its hardware qualification. For example, Sensors, Actuators, and ASICs with dedicated functionality.
- Complex component: Hardware components which are capable to compute and/or drive decisions of the system can be classified as a complex component. These components are subjected to be developed in compliance with the entire ISO 26262 standard. For example, Microprocessor, Microcontroller, DSP, and accelerator.
The table above is a summary of the qualification and integration of basic parts, hardware parts and components. The highlighted circles in the table indicate that standard qualification is sufficient for a basic part and the use of ISO 26262-4 and ISO 26262-5. The integration/test depends on the level of the intermediate part or component.
Hardware qualification of intermediate parts or components can be done using two different methods: testing or analysis. During testing, the hardware component or part is exposed to the intended environmental and operational conditions. Compliance with its functional requirements is then assessed. The qualification through analysis relies on rationale for analytical methods and assumptions used.
Hardware qualification can be applied based on the interpretation of the design abstraction by the developer. Hence it is evident that hardware qualification is an offbeat from the strenuous ISO 26262 process.