Dave,

Thanks for your support and interest.

Having got it to work using the 'end-loop' process you suggested, I had a further play-around with the interrupts - and made it work!

I added the code:

Code:
bcf  RCON,7    ; Clear IPEN=0, disable priority interrupts
And now all is OK.

If anyone is interested in the code I'm happy to put it up here. The routine uses ASM to:

1. Drive 2 stepper motors at the same time.
2. Main purpose is to get diagonal moves on an XY plotter
3. The asm code is passed parameters by PBP:
a. X steps to be done
b. Y steps to be done
c. X inter-pulse delay
d. Y inter-pulse delay
4. Code has yet to be 'polished' and oly works with byte size parameters.
Next is changing to accept WORD size parameters.

Once again - thanks for your help.

Regards Bill Legge