RM0444 Rev 5 515/1390
RM0444 AES hardware accelerator (AES)
522
20.7.4 AES data output register (AES_DOUTR)
Address offset: 0x0C
Reset value: 0x0000 0000
Only 32-bit read access type is supported.
Bits 31:0 DIN[31:0]: Input data word
A four-fold sequential write to this bitfield during the input phase results in writing a complete 128-bit
block of input data to the AES peripheral. From the first to the fourth write, the corresponding data
weights are [127:96], [95:64], [63:32], and [31:0]. Upon each write, the data from the 32-bit input
buffer are handled by the data swap block according to the DATATYPE[1:0] bitfield, then written into
the AES core 128-bit input buffer.
The data signification of the input data block depends on the AES operating mode:
- Mode 1 (encryption): plaintext
- Mode 2 (key derivation): the bitfield is not used (AES_KEYRx registers used for input)
- Mode 3 (decryption) and Mode 4 (key derivation then single decryption): ciphertext
The data swap operation is described in Section 20.4.13: AES data registers and data swapping on
page 505.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
DOUT[31:16]
rrrrrrrrrrrrrrrr
1514131211109876543210
DOUT[15:0]
rrrrrrrrrrrrrrrr
Bits 31:0 DOUT[31:0]: Output data word
This read-only bitfield fetches a 32-bit output buffer. A four-fold sequential read of this bitfield, upon
the computation completion (CCF set), virtually reads a complete 128-bit block of output data from
the AES peripheral. Before reaching the output buffer, the data produced by the AES core are
handled by the data swap block according to the DATATYPE[1:0] bitfield.
Data weights from the first to the fourth read operation are: [127:96], [95:64], [63:32], and [31:0].
The data signification of the output data block depends on the AES operating mode:
- Mode 1 (encryption): ciphertext
- Mode 2 (key derivation): the bitfield is not used
- Mode 3 (decryption) and Mode 4 (key derivation then single decryption): plaintext
The data swap operation is described in Section 20.4.13: AES data registers and data swapping on
page 505.
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