Another scenario is that you have gone through the above with the emulator connected(getting the Illegal ISR) and then if you disconnect the emulator and just issue XRSn to start over, again the value is still present in memory so things work OK.
Another scenario is that you have gone through the above with the emulator connected(getting the Illegal ISR) and then if you disconnect the emulator and just issue XRSn to start over, again the value is still present in memory so things work OK.