With regards CRC on AD7606B

Hi , 

I have a few questions with regard to CRC on AD7606B.

1. On setting Register 0x21 to enable CRC, when will CRC be active. Should we read with CRC from the next command is it.

2.Will the CRC register be all 0 when enabling CRC in  Register in Register mode. With regards to ADC mode, we can see the detail in datasheet.

3.Will the CRC register be all 0 when you enable the CRC in ADC mode.

Thanking you 

With best regards and wishes