NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 978 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
TDES/DES Control Register (CRPT_TDES_CTL)
Register
Offset
R/W
Description
Reset Value
CRPT_TDES_CTL
0x200 R/W
TDES/DES Control Register
0x0000_0000
31
30
29
28
27
26
25
24
KEYPRT
KEYUNPRT
CHANNEL
23
22
21
20
19
18
17
16
INSWAP
OUTSWAP
BLKSWAP
Reserved
ENCRPT
15
14
13
12
11
10
9
8
Reserved
OPMODE
7
6
5
4
3
2
1
0
DMAEN
DMACSCAD
DMALAST
Reserved
3KEYS
TMODE
STOP
START
Bits
Description
[31]
KEYPRT
Protect Key
Read as a flag to reflect KEYPRT.
0 = No effect.
1 = This bit is to protect the content of TDES key from reading. The return
value for reading CRPT_ TDESn_KEYxH/L is not the content in the registers
CRPT_ TDESn_KEYxH/L. Once it is set, it can be cleared by asserting
KEYUNPRT. The key content would be cleared as well.
[30:26]
KEYUNPRT
Unprotect Key
Writing 0 to CRPT_TDES_CTL [31] and “10110” to CRPT_TDES_CTL
[30:26] is to unprotect TDES key.
The KEYUNPRT can be read and written. When it is written as the TDES
engine is operating, BUSY flag is 1, there would be no effect on
KEYUNPRT.
[25:24]
CHANNEL
TDES/DES Engine Working Channel
00 = Current control register setting is for channel 0.
01 = Current control register setting is for channel 1.
10 = Current control register setting is for channel 2.
11 = Current control register setting is for channel 3.
[23]
INSWAP
TDES/DES Engine Input Data Swap
0 = Keep the original order.
1 = The order that CPU feeds data to the accelerator will be changed from
{byte3, byte2, byte1, byte0} to {byte0, byte1, byte2, byte3}.
[22]
OUTSWAP
TDES/DES Engine Output Data Swap
0 = Keep the original order.
1 = The order that CPU outputs data from the accelerator will be changed
from {byte3, byte2, byte1, byte0} to {byte0, byte1, byte2, byte3}.