Hi Joannes,
The one signal that is not shown is DRDY. The ADS1248 defaults to RDATAC mode which will automatically place the latest contents of the conversion result to the output buffer as soon as DRDY transitions from high to low. If this transition happens at the wrong time (when you are reading registers for example) you will get corrupted data. I always use the same sequence when I read and write registers, and that is to issue the SDATAC command first. This command stops automatic placement of the results into the output register. The SDATAC command takes effect after the current conversion result is posted.
I would suggest that until you have fully verified that communication you use SDATAC right away (first thing you send to the device), then you don't have to worry about any issues related to the automatic posting of results.
Best regards,
Bob B