We've been using ADIS16250/ADISG16265/ADIS16364 for many years here. This will seem like a funny question:
Can I read or write the following non-existent registers without causing any problem in the part?
ADIS16250: read and write register offset 0 and offset 0x7f.
ADIS16265: read and write register offset 0 and offset 0x7f (I know read of register 0 is OK)
ADIS16364: read and write register offset 0 and offset 0x7f (I know read of register 0 is OK)
A write would be writing all 1s.
The values read from these registers are discarded by our software so that is good.
Does these erroneous accesses cause any ill effects in the hardware?
You are probably asking, why don't we just fix the software bug. The problem is that code is about 7 years old and the way our company works, I'm not allowed to fix this problem unless there is a defect that will affect a customer. We haven't seen any problems over the years but if this is really bad I'd like to know and then I can demand it gets fixed.