5.1.7 SelfTest Command

The SelfTest command performs a test of one or more of the cryptographic engines within the ATECC608B-TNGLoRaWAN chip. Some or all of the algorithms will be tested depending on the Input mode parameter.

For the ATECC608B-TNGLoRaWAN device, the SelfTest command has been disabled from running automatically after a Power-up or Wake event. However, the command may be executed by the system if so desired. There is no requirement to run this test.

If any self test fails, whether called automatically on power-up, wake or via this command, the chip will enter a Failure state, in which chip operation is limited. The stored Failure state is always cleared upon a wake or power cycle. Note that the self-test failure (error code: 0x07) is not the same as a health-test failure (error code: 0x08).

When in the Failure state, the following operations are allowed:

• Reads of the Configuration zone.
• This self-test command. If a particular test is re-run and passes on the subsequent attempt, that bit in the Failure register will be cleared. If all bits are cleared, then ATECC608B-TNGLoRaWAN resumes normal command operation.
• The current state of the Failure register can be read by calling this self-test command with a mode parameter of 0.
• Any other command or reads of any other zone, will return an error code of 0x07. Use SelfTest(0) to determine the cause of the failure