20.4.18 Self Test Features

The QEIxIOC register contains override bits, which allow the user to inject an artificial input into the QEIx module for a module health test. This function allows the user to inject an artificial input into the module and observe the expected response to ensure the module's proper operation.

This self-test allows functional safety focused customers to exercise the module with the known input and output responses for a module health test. The QEIxIOC[31:24] register contains individual override bits, which allow the user to inject an artificial individual input into the QEIx module for a self-test.

The QEI state and status registers cannot be written directly. Instead, the input override logic is used to cause errors. The QEIx count registers may be incorrect and it may not be possible to regain the correct QEI count when disabling the override. The override function intent is for the functional safety software to check operation and then disable overrides and reset the QEI count to zero.