Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet

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SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13

The fuse states are automatically read on CORE startup and are available for reading in the 10 Fuse Status (FUSE_SRx)
registers.

The fuse states of bits 31 to 0 will be available at FUSE_SR0, the fuse states of bits 63 to 32 will be available at
FUSE_SR1 and so on.

FUSE_SRx registers can be updated manually by using the RRQ bit of the Fuse Control register (FUSE_CR). RS and
WS bits of the Fuse Index register (FUSE_IR) must be at level one before issuing the read request.

All the fuses can be written by software. To program fuses, strictly follow the order of the sequence instructions as
provided below:

1.

Select the word to write, using the SELW field of the Fuse_Index register (FUSE_IR).

2.

Write the word to program in the Fuse_Data register (FUSE_DR). 

3.

Check that RS and WS bits of the Fuse_Index register are at level one (no read and no write pending).

4.

Write the WRQ bit of the Fuse_Control register (FUSE_CR) to begin the fuse programming. The KEY field must be 
written at the same time with a value 0xFB to make the write request valid. Writing the WRQ bit will clear the WS 
bit.

5.

Check the WS bit of FUSE_SRx, when WS has a value of “1” the fuse write process is over.

Only fuses to be set to level “1” are written.

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Clock

FUSE_SRx

RRQ

WS

RS

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