Functional safety requirements for application software

AN4475

10/27

DocID026216 Rev 1

2.6

Interrupt Controller (INTC)

Suggested: [covers: SW_INTC_APPLICATION] integrity of the INTC module is checked.

These specific software countermeasures can run once after the Power-On Reset (POR)

before the safety application starts. [end]

Implementation hint: e.g. the INTC module is configured to generate some interrupt

requests and the expected behavior is verified.

Suggested: [covers: SW_ISR_SELF_TEST] considering that no specific hardware

protection is implemented against failures in the Interrupt Controller, spurious/missing

interrupt requests caused by Electromagnetic Interference (EMI) or by bit flips in the

interrupt registers of the peripherals, applications not resilient against such errors are

included detection or protection software countermeasures. These specific software

countermeasures can run for each interrupt request. [end]

Rationale: to verify interrupt requests are serviced correctly.

Implementation hint: e.g. spurious interrupts can be detected checking corresponding

interrupt status in the interrupt status register of the related peripheral before executing the

Interrupt Service Routine (ISR) code and missing interrupts, if they are synchronous, can be

detected checking the program flow.

2.7

Enhanced Direct Memory Access (eDMA)

Suggested: [covers: SW_DMA_APPLICATION] considering that no specific hardware

protection is implemented against failures in the eDMA, spurious/missing eDMA requests

caused by Electromagnetic Interference (EMI) or by bit flips in the interrupt registers of the

peripherals, applications not resilient against such errors are included detection or

protection software countermeasures. These specific software countermeasures can run

once after the Power-On Reset (POR) before running the SIF. [end]

Rationale: to verify eDMA requests are serviced correctly.

Implementation hint: specific software countermeasures are implemented to detect eDMA

permanent faults. These specific software countermeasures are application-dependent.

2.8

Communication peripherals

The SPC563Mxx includes the following communication peripherals:

•

FlexCAN

•

Deserial Serial Peripheral Interface (DSPI)

•

Enhanced Serial Communication Interface (eSCI)

Suggested: [covers: SW_xxx_FT_COMM_PROT] an appropriate safety software protocol

should be implemented (e.g. Fault Tolerant Communication Layer or FTCOM) for any

communication peripheral employed to meet safety application requirements. [end]