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GD32L23x User Manual
578
23.9.
Register definition
CAU base address: 0x5006 0000
23.9.1.
Control register (CAU_CTL)
Address offset: 0x00
Reset value: 0x0000 0000
This register has to be accessed by word (32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
NBPILB[3:0]
ALGM[3] Reserved GCM_CCMPH[1:0]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
CAUEN
FFLUSH
Reserved
KEYM[1:0]
DATAM[1:0]
ALGM[2:0]
CAUDIR
Reserved
rw
w
rw
rw
rw
rw
Bits
Fields
Descriptions
31:24
Reserved
Must be kept at reset value.
23:20
NBPILB[3:0]
Number of bytes padding in last block of payload
0000: all bytes are valid (no padding)
0001: one padding byte of last block
...
1111: 15 padding bytes of last block
19
ALGM[3]
Encryption/decryption algorithm mode bit 3
18
Reserved
Must be kept at reset value.
17:16
GCM_CCMPH[1:0]
GCM CCM phase
00: prepare phase
01: AAD phase
10: encryption/decryption phase
11: tag phase
15
CAUEN
CAU Enable
0: CAU is disabled
1: CAU is enabled
Note:
the CAUEN can be cleared automatically when the key derivation
(ALGM=0111b) is finished or the AES-GCM or AES-CCM initial phase finished.
14
FFLUSH
Flush FIFO
0: No effect
1: When CAUEN=1, flush the input and output FIFO