AN4266 datasheet(21/76 Pages) STMICROELECTRONICS

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AN4266

Functional safety requirements for application software

Doc ID 024283 Rev 2

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Figure 2.

Double Read PWM Input

Software test implementation

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ETIMER0_SWTEST_REGCRC

The eTimer_0 configuration registers are read and a CRC checksum is computed. The

checksum is compared with the expected value.

●

ETIMER1_SWTEST_REGCRC

The eTimer_1 configuration registers are read and a CRC checksum is computed. The

checksum is compared with the expected value.

●

SIUL_SWTEST_REGCRC

The configuration registers of the SIUL are read and a CRC checksum is computed.

The checksum is compared with the expected value.

Note:

Implementation hint: The eDMA and CRC modules should be used to implement these

SIFs to avoid overloading the CPU.

●

ETIMERI_SWTEST_CMP

This software BIST is used to execute the comparison between the double reads

performed by a channel on eTimer_0 and another channel on eTimer_1. The

comparison must take into account possible approximation because of different

capturing of the input asynchronous signals.

Implementation details

The following hardware elements shall be used for the safety function:

●

eTimer_0 channels

●

eTimer_1 channels

PWM In Double Read

Configuration

ETC[x]

ETC[y]

eTimer_0

eTimer_1

= Input Pad

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