Datasheet

1013
SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]
11063K–ATARM–05-Nov-13
• OPMOD: Operation Mode
Values which are not listed in the table must be considered as “reserved”.
For CBC-MAC operating mode, please set OPMOD to CBC and LOD to 1.
•LOD: Last Output Data Mode
0: No effect.
After each end of encryption/decryption, the output data are available either on the output data registers (Manual and Auto
modes) or at the address specified in the Channel Buffer Transfer Descriptor for DMA mode.
In Manual and Auto modes, the DATRDY flag is cleared when at least one of the Output Data registers is read.
1: The DATRDY flag is cleared when at least one of the Input Data Registers is written.
No more Output Data Register reads is necessary between consecutive encryptions/decryptions (see “Last Output Data Mode”
on page 1006).
Warning
: In DMA mode, reading to the Output Data registers before the last data encryption/decryption process may lead to unpre-
dictable results.
• CFBS: Cipher Feedback Data Size
Values which are not listed in table must be considered as “reserved”.
• CKEY: Key
Value Name Description
0x0 ECB ECB: Electronic Code Book mode
0x1 CBC CBC: Cipher Block Chaining mode
0x2 OFB OFB: Output Feedback mode
0x3 CFB CFB: Cipher Feedback mode
0x4 CTR CTR: Counter mode (16-bit internal counter)
Value Name Description
0x0 SIZE_128BIT 128-bit
0x1 SIZE_64BIT 64-bit
0x2 SIZE_32BIT 32-bit
0x3 SIZE_16BIT 16-bit
0x4 SIZE_8BIT 8-bit
Value Name Description
0xE PASSWD
This field must be written with 0xE the first time that AES_MR is programmed. For subsequent
programming of the AES_MR, any value can be written, including that of 0xE.
Always reads as 0.