57.1 Description

The Secure Fuse Controller (SFC) interfaces the system with electrical fuses in a secure way.

The default value of a fuse is logic ‘0’ (not programmed). A programmed fuse is logic ‘1’.

An electrical fuse matrix is a type of non-volatile memory. Each fuse in the matrix can be programmed only one time. They are typically used to store calibration bits for analog cells such as oscillators, configuration settings, chip identifiers or cryptographic keys.

A specific number of fuse bits are programmed during the production tests. The remaining 544 fuse bits are programmed by the user and by software through the user interface.

The SFC automatically reads the fuse values on start-up and stores them in 32-bit registers in order to make them accessible by the software. Only fuses set to level ‘1’ are programmed.