Datasheet

1012
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
45.6.2 AES Mode Register
Name: AES_MR
Address: 0xF000C004
Access: Read-write
• CIPHER: Processing Mode
0: Decrypts data.
1: Encrypts data.
• DUALBUFF: Dual Input Buffer
• PROCDLY: Processing Delay
The Processing Time represents the number of clock cycles that the AES needs in order to perform one encryption/decryption.
Note: The best performance is achieved with PROCDLY equal to 0.
• SMOD: Start Mode
Values which are not listed in the table must be considered as “reserved”.
If a DMA transfer is used, 0x2 must be configured. Refer to Section 45.4.3.3 ”DMA Mode” for more details.
• KEYSIZE: Key Size
Values which are not listed in the table must be considered as “reserved”.
31 30 29 28 27 26 25 24
––––––––
23 22 21 20 19 18 17 16
CKEY – CFBS
15 14 13 12 11 10 9 8
LOD OPMOD KEYSIZE SMOD
76543210
PROCDLY DUALBUFF – – CIPHER
Value Name Description
0x0 INACTIVE AES_IDATARx cannot be written during processing of previous block.
0x1 ACTIVE
AES_IDATARx can be written during processing of previous block when SMOD = 0x2. It
speeds up the overall runtime of large files.
Value Name Description
0x0 MANUAL_START Manual Mode
0x1 AUTO_START Auto Mode
0x2 IDATAR0_START AES_IDATAR0 access only Auto Mode
Value Name Description
0x0 AES128 AES Key Size is 128 bits
0x1 AES192 AES Key Size is 192 bits
0x2 AES256 AES Key Size is 256 bits
Processing Time 12 PROCDLY 1+()×=