37.8.1 Control A
| Name: | CTRLA |
| Offset: | 0x00 |
| Reset: | 0x00000000 |
| Property: | PAC Write-Protection, Enable-protected |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| CTYPE[3:0] | |||||||||
| Access | R/W | R/W | R/W | R/W | |||||
| Reset | 0 | 0 | 0 | 0 | |||||
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| XORKEY | KEYGEN | LOD | STARTMODE | CIPHER | KEYSIZE[1:0] | ||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | ||
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| CFBS[2:0] | AESMODE[2:0] | ENABLE | SWRST | ||||||
| Access | R/W | R/W | R/W | R/W | R/W | R/W | R/W | R/W | |
| Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | |
Bits 19:16 – CTYPE[3:0] Countermeasure type
| Value | Name | Description |
|---|---|---|
| XXX0 | CTYPE1 disabled | Countermeasure1 disabled |
| XXX1 | CTYPE1 enabled | Countermeasure1 enabled |
| XX0X | CTYPE2 disabled | Countermeasure2 disabled |
| XX1X | CTYPE2 enabled | Countermeasure2 enabled |
| X0XX | CTYPE3 disabled | Countermeasure3 disabled |
| X1XX | CTYPE3 enabled | Countermeasure3 enabled |
| 0XXX | CTYPE4 disabled | Countermeasure4 disabled |
| 1XXX | CTYPE4 enabled | Countermeasure4 enabled |
Bit 14 – XORKEY XOR Key
| Value | Description |
|---|---|
| 0 | No effect |
| 1 | The user keyword gets XORed with the previous keyword register content. |
Bit 13 – KEYGEN Key Generation
| Value | Description |
|---|---|
| 0 | No effect |
| 1 | Start Computation of the last NK words of the expanded key |
Bit 12 – LOD Last Output Data Mode
| Value | Description |
|---|---|
| 0 | No effect |
| 1 | Start encryption in Last Output Data mode |
Bit 11 – STARTMODE Start Mode Select
| Value | Name | Description |
|---|---|---|
| 0 | Manual Mode | Start Encryption / Decryption in Manual mode |
| 1 | Auto Mode | Start Encryption / Decryption in Auto mode |
Bit 10 – CIPHER Encryption/ Decryption
| Value | Description |
|---|---|
| 0 | Decryption |
| 1 | Encryption |
Bits 9:8 – KEYSIZE[1:0] Encryption Key Size
| Value | Name | Description |
|---|---|---|
| 0 | 128-bit Key | 128-bit Key for Encryption / Decryption |
| 1 | 192-bit Key | 192-bit Key for Encryption / Decryption |
| 2 | 256-bit Key | 256-bit Key for Encryption / Decryption |
| 3 | Reserved | Reserved |
Bits 7:5 – CFBS[2:0] Cipher Feedback Block Size
| Value | Name | Description |
|---|---|---|
| 0 | 128-bit data block | 128-bit Input data block for Encryption/Decryption in Cipher Feedback mode |
| 1 | 64-bit data block | 64-bit Input data block for Encryption/Decryption in Cipher Feedback mode |
| 2 | 32-bit data block | 32-bit Input data block for Encryption/Decryption in Cipher Feedback mode |
| 3 | 16-bit data block | 16-bit Input data block for Encryption/Decryption in Cipher Feedback mode |
| 4 | 8-bit data block | 8-bit Input data block for Encryption/Decryption in Cipher Feedback mode |
| 5-7 | Reserved | Reserved |
Bits 4:2 – AESMODE[2:0] AES Modes of Operation
| Value | Name | Description |
|---|---|---|
| 0 | ECB | Electronic code book mode |
| 1 | CBC | Cipher block chaining mode |
| 2 | OFB | Output feedback mode |
| 3 | CFB | Cipher feedback mode |
| 4 | Counter | Counter mode |
| 5 | CCM | CCM mode |
| 6 | GCM | Galois counter mode |
| 7 | Reserved | Reserved |
Bit 1 – ENABLE Enable
| Value | Description |
|---|---|
| 0 | The peripheral is disabled |
| 1 | The peripheral is enabled |
Bit 0 – SWRST Software Reset
Writing a '0' to this bit has no effect.
Writing a '1' to this bit resets all registers in the AES module to their initial state, and the module will be disabled.
Writing a '1' to SWRST will always take precedence,
meaning that all other writes in the same write operation will be discarded.
| Value | Description |
|---|---|
| 0 | There is no reset operation ongoing |
| 1 | The reset operation is ongoing |