The comparator test interface allows injecting faults in any bit of a comparator, in combination with the TMR Comparator AXI4-Stream test interface. Typically a test sequence would consist of the following steps:
• Set the TMR Manager compare mask to mask faults from the tested comparator.
• Inject all possible faults and verify that they are correctly detected:
° Use the AXI4-Stream test connection to the TMR Comparator to shift in an erroneous bit into the tested comparator.
° Set the comparator test interface to inject the fault in the tested comparator.
° Shift out the result via the AXI4-Stream test connection and verify that the fault has been detected by the comparator.
° Repeat for all bits in the comparator interface and all possible faults.
• Reset the TMR Manager compare mask for nominal operation.
• Repeat for all comparators.
Optionally, the TMR Manager can be allowed to handle the injected fault provided that debug is enabled, by not setting the TMR Manager compare mask. In that case, the Control Register should be set up to block the Break signal. Return to nominal operation is done by using the Reset Failing State Register.