RM0082
AS_Cryptographic co-processor (C3)
Doc ID 018672 Rev 1
387/844
21.8.13
Feedback registers (DES_FEEDBACK)
The Feedback Registers contain the value that is added to the DES input for implementing
the selected mode of operation (it depends on the selected mode).
21.8.14
Control and status register (DES_CONTROL_STATUS)
●
Bits 31 to 3 - Reserved
These bits are reserved and should be written zero.
●
Bit 2 - Encryption/Decryption (ED)
This bit indicates the operation to perform (Encryption or Decryption).
●
Bit 1 - Mode of operation (MODE)
This bit indicates the mode of operation (ECB or CBC).
Bit
31
30
29
28
27
26
25
24
Symbol
res
res
res
res
res
res
res
res
Initial Value
-
-
-
-
-
-
-
-
Type
-
-
-
-
-
-
-
-
Bit
23
22
21
20
19
18
17
16
Symbol
res
res
res
res
res
res
res
res
Initial Value
-
-
-
-
-
-
-
-
Type
-
-
-
-
-
-
-
-
Bit
15
14
13
12
11
10
9
8
Symbol
res
res
res
res
res
res
res
res
Initial Value
-
-
-
-
-
-
-
-
Type
-
-
-
-
-
-
-
-
Bit
7
6
5
4
3
2
1
0
Symbol
res
res
res
res
res
ED
MODE
ALGO
Initial Value
-
-
-
-
-
0
0
0
Type
-
-
-
-
-
R/W
R/W
R/W
Bit 2
Description
1’b0
Encryption
1’b1
Decryption