I would agree.....since I've done this many a time but it does indeed keep the timers from incrementing (and the LED from flashing) in the ISR. I can do the return...everything is fine. Another strange one...that happened again last night and thought I had it all working was table reads. I've just copied over code that has worked many a time, but now it appears to read the table once...and then it wont return with the info any other times but the first time. I failed to mention, this is an 18F4680 device. This was with actual hardware, going to run in sim mode later this morning and see if it 'behaves' then. Jinx wrote: > any idea? Can't see a problem with the code......must be something else (duh) I seriously doubt there's an issue with writing to RAM per se. That would undermine the whole operation of the PIC. There'll be a non- obvious problem (non-obvious until you see what it is) lurking just out of sight -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist --------------------------------- TV dinner still cooling? Check out "Tonight's Picks" on Yahoo! TV. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist