Some bits must survive every reset, every sleep and every firmware update: oscillator trim, boot configuration, memory repair addresses and the device's secrets. NanoSoC keeps them in one-time-programmable fuses read once at reset into shadow registers. This topic teaches what lives in the array, when it is read and distributed, and the three integration risks that follow from memory that can never be erased. Fuse field allocations here are NanoSoC teaching values, because the NanoSoC reference table defines the need but not the map. These lessons carry the whole subject for the course.
Lesson | After it you can... |
|---|---|
Allocate fuse fields for trim, configuration, repair and secrets. | |
Sequence fuse read-out before first use and check every consumer. | |
Route repair fuses to the SRAM wrappers and manage lifecycle states. |
Suggested order: top to bottom. Allocate the fields first, because timing and routing both follow the allocation; then sequence the read-out; then connect repair and lifecycle. The secure-boot topic consumes the key and version fields defined here.
Because the array is slow, power-hungry and readable only in a special mode. One sequenced read at reset copies each field into an ordinary flop near its consumer, and normal logic never touches the array again.