Datasheet

42.8.2 Control B
Name: CTRLB
Offset: 0x04
Reset: 0x00
Property: PAC Write-Protection
Bit 7 6 5 4 3 2 1 0
GFMUL EOM NEWMSG START
Access
R/W R/W R/W R/W
Reset 0 0 0 0
Bit 3 – GFMUL GF Multiplication
This bit is applicable only to GCM mode.
Value Description
0
No action
1
Setting this bit calculates GF multiplication with data buffer content and hashkey register
content.
Bit 2 – EOM End of Message
This bit is applicable only to GCM mode.
Value Description
0
No action
1
Setting this bit generates final GHASH value for the message.
Bit 1 – NEWMSG New Message
This bit is used in cipher block chaining (CBC), cipher feedback (CFB) and output feedback (OFB),
counter (CTR) modes to indicate the hardware to use Initialization vector for encrypting the first block of
message.
Value Description
0
No action
1
Setting this bit indicates start of new message to the module.
Bit 0 – START Start Encryption/Decryption
Value Description
0
No action
1
Start encryption / decryption in manual mode.
SAM D5x/E5x Family Data Sheet
AES – Advanced Encryption Standard
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1430