38.8.5 Interrupt Flag Status and Clear

Name: INTFLAG
Offset: 0x07
Reset: 0x00

Bit 76543210 
       GFMCMPENCCMP 
Access R/WR/W 
Reset 00 

Bit 1 – GFMCMP GF Multiplication Complete

This flag is cleared by writing a '1' to it.

This flag is set when GHASH value is available on the Galois Hash Registers (GHASHx) in GCM mode.

Writing a '0' to this bit has no effect.

This flag is also automatically cleared in the following cases.

  1. Manual encryption/decryption occurs (START in CTRLB register).
  2. Reading from the GHASHx register.

Bit 0 – ENCCMP Encryption Complete

This flag is cleared by writing a '1' to it.

This flag is set when encryption/decryption is complete and valid data is available on the Data Register.

Writing a '0' to this bit has no effect.

This flag is also automatically cleared in the following cases:

  1. Manual encryption/decryption occurs (START in CTRLA register). (This feature is needed only if we do not support double buffering of DATA registers).
  2. Reading from the data register (DATAx) when LOD = 0.
  3. Writing into the data register (DATAx) when LOD = 1.
  4. Reading from the Hash Key register (HASHKEYx).