AES Registers: Difference between revisions
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The contents of the keyslot specified in REG_AESKEYCNT can be updated by consecutively writing four words to REG_AESKEYXFIFO (keyX), REG_AESKEYYFIFO(keyY), or REG_AESKEYFIFO (normalkey). | The contents of the keyslot specified in REG_AESKEYCNT can be updated by consecutively writing four words to REG_AESKEYXFIFO (keyX), REG_AESKEYYFIFO(keyY), or REG_AESKEYFIFO (normalkey). | ||
After writing to a keyslot, the keyslot must be selected again(write REG_AESKEYSEL + set REG_AESCNT bit26), | After writing to a keyslot when that same keyslot is already selected via REG_AESKEYSEL, the keyslot must be selected again(write REG_AESKEYSEL + set REG_AESCNT bit26), in order for the AES engine to use the new key-data. | ||
Writing to the key FIFOs with byte writes results in the AES engine converting the byte to a word for setting the key word, with this: word = (byteval) | (byteval<<8) | (byteval<<16) | (byteval<<24). The result is the same regardless of which FIFO register byte was written to. | Writing to the key FIFOs with byte writes results in the AES engine converting the byte to a word for setting the key word, with this: word = (byteval) | (byteval<<8) | (byteval<<16) | (byteval<<24). The result is the same regardless of which FIFO register byte was written to. | ||