Hi Art,
The HC05 did not have a H register, so if you are simply converting code you can ignore it completely. No need to push/pull it if you never change or use it.
The HC05 had the stack fixed at $FF with no need to change it so it should still work here when you convert. This is why it defaults to $FF in an S08 to maintain compatibility. The only reason it would not convert is if there was less available RAM between the top of the registers and $FF and the old one was using this much.
So, these are only reasons why these two things won't be causing the problem.
As for what is:
Do you have branches out of your ISR that may mean that it never gets back to execute the RTI?
In your last post you corrected to RTS, is this correct? Or did you mean RTI?
Putting RTS where you should have RTI will cause problems.
Have you accidently put in some of the new stack manipulation instructions somewhere that don't have the corresponding "undo" part for? Do a search on your code for AIS and the like, you should not have any if you are converting '05 code.
Message Edited by peg on
2009-01-13 08:11 AM