Self tests for SPC564Ax core subsystem

AN3018

14/24

Doc ID 16081 Rev 2

Figure 2.

Parallel signature unit

Several CPU tests can be implemented:

–Register test

–

Arithmetic and logic unit test

–

Control flag test

–

Branch test

The parallel, available on any SPC564Ax variant, allows the acceleration of the tests by

computing a signature and avoiding single register comparison to an external reference.

Principle: use software based tests to check the CPU core. Instead of comparing CPU

registers to a reference, use the CRC unit to compute a signature by writing the register

content to the CRC unit. The CRC can be seeded to any value by initializing the CRC before

the test.

Result: once the test is completed, the signature in the CRC unit can be compared with the

reference signature.

Resource availability: the CPU module is available during this test. Interrupts should be

masked during the execution of the test as the content of the parallel signature unit would be

modified during the execution of the interrupt routine.