Tag Generation
- Configure CTRLA
- 1.Set CTRLA.ENABLE to 0
- 2.Set CTRLA.AESMODE as CTR
- 3.Set CTRLA.ENABLE to 1
- Load J0 value to INITVECTVx reg.
- Load GHASHx value to DATA reg.
- Set CTRLB.NEWMSG and CTRLB.START to start the Counter mode operation.
- Wait for INTFLAG.ENCCMP to be set.
- AES Hardware generates the GCM Tag output in DATA register.