54.5.5.4 Start Operation

During the Start operation, the SRAM startup values and the activation code that was generated during enroll are used to reconstruct the intrinsic PUF key. When the activation code of another device is used, reconstruction fails, and the PUF controller responds with an error indication.

After successful completion of the Start operation, diagnostic information about the PUF quality is provided in PUF_PSR (see PUF Diagnostics for details).

Note: The PUF scores returned after a Start (or Reconstruct) operation and Enroll (or Test PUF) operation can differ, because these operations measure PUF quality in different ways.

Start operates in two phases (Reconstruction and Anti-aging), each requiring the activation code. Therefore the activation code must be sent twice during a Start operation.