Hello Lundin,
To use the DG128 header file, the main difference for the ATD module seems to be that all register names previously identified by the prefix ATD... within your code, should now have the prefix ATD0... , to suit the proper header file for the new device.
Has this already been taken into account? You do not say whether the code is failing to compile, or it is compiling but does not work as expected.
The use of bit fields, unions and macros to define individual bits within a register seems to be the "CW way". I don't believe there is any compulsion to use these if you wish to create your own bit mask definitions. However, I think that the standard register names should continue to be used.
Regards,
Mac