Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet
Product codes
ATSAM4E-XPRO
SAM4E [DATASHEET]
Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14
632
31.4.4.1 Manual and Auto Modes
If LOD = 0
The DATRDY flag is cleared when at least one of the AES_ODATARx is read (See
).
Figure 31-1.
Manual and Auto Modes with LOD = 0
If the user does not want to read the AES_ODATARx between each encryption/decryption, the DATRDY flag will
not be cleared. If the DATRDY flag is not cleared, the user cannot know the end of the following
encryptions/decryptions.
not be cleared. If the DATRDY flag is not cleared, the user cannot know the end of the following
encryptions/decryptions.
If LOD = 1
The DATRDY flag is cleared when at least one AES_IDATAR is written (See
). No more
AES_ODATAR reads are necessary between consecutive encryptions/decryptions.
Figure 31-2.
Manual and Auto Modes with LOD = 1
31.4.4.2 DMA Mode
If LOD = 0
This mode may be used for all AES operating modes except CBC-MAC where LOD = 1 mode is recommended.
The end of the encryption/decryption is indicated by the end of DMA transfer associated to AES_ODATARx (see
). Two DMA channels are required: one for writing message blocks to AES_IDATARx and one to obtain
the result from AES_ODATARx.
Encryption or Decryption Process
Read the AES_ODATARx
Write START bit in AES_CR (Manual mode)
DATRDY
Write AES_IDATARx register(s) (Auto mode)
or
Write AES_IDATARx register(s)
Write START bit in AES_CR (Manual mode)
Write AES_IDATARx register(s) (Auto mode)
or
Encryption or Decryption Process
DATRDY