
Advanced encryption standard hardware accelerator (AES)
RM0351
840/1830
DocID024597 Rev 5
28.14 AES
registers
28.14.1 AES control register (AES_CR)
Address offset: 0x00
Reset value: 0x0000 0000
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
KEY
SIZE
Res.
CH
MOD
[2]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
GCMPH[1:0]
DMA
OUT
EN
DMA
INEN
ERRIE CCFIE
ERRC
CCFC
CHMOD[1:0]
MODE[1:0]
DATATYPE[1:0]
EN
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:19 Reserved, must be kept at reset value.
Bit 18
KEYSIZE:
Key size selection
0: 128 bit key length
1: 256 bit key length
The operation mode must only be changed if the AES is disabled. Writing these bits while the AES is
enabled is forbidden in order to avoid unpredictable AES behavior.
Bits 17, 15 Reserved, must be kept at reset value.
Bits 14:13
GCMPH[1:0]:
Used only for GCM, GMAC and CMAC algorithms and has no effect when other
algorithms are selected
00: GCM init Phase
01: GCM header phase
10: GCM payload phase
11: GCM final phase
Note: GCM init phase and GCM payload phase must not be used when CMAC is selected, else AES
peripheral behavior is not guaranteed.
Bit 12
DMAOUTEN:
Enable DMA management of data output phase
0: DMA (during data output phase) disabled
1: DMA (during data output phase) enabled
If the DMAOUTEN bit is set, DMA requests are generated for the output data phase in mode 1, 3 or
4. This bit has no effect in mode 2 (key derivation).
Bit 11
DMAINEN:
Enable DMA management of data input phase
0: DMA (during data input phase) disabled
1: DMA (during data input phase) enabled
If the DMAINEN bit is set, DMA requests are generated for the data input phase in mode 1, 3 or 4. This
bit has no action in mode 2 (key derivation).
Bit 10
ERRIE
: Error interrupt enable
An interrupt is generated if at least one of the both flags RDERR or WRERR is set.
0: Error interrupt disabled
1: Error interrupt enabled