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Posted By

okalex on 11/29/06


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Pic Picbasic Interrupt Assembly


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PIC Interrupt Context Save and Restore

Published in: Assembler 

This code is used to save and restore the context registers of a PIC18F device before executing an interrupt service routine. FSR0 only needs to be saved


Plain TextExpand 
  1. ISR:
  2. ; Save processor context
  3. movwf	wSave, 0
  4. movff	STATUS, statSave
  5. movff	BSR, bsrSave
  6.  
  7. ; Save FSR0
  8. movff	FSR0L, fsr0lSave
  9. movff	FSR0H, fsr0hSave
  10.  
  11. ; Insert code here
  12.  
  13. End_Isr:
  14. ; Restore FSR0
  15. movff	fsr0lSave, FSR0L
  16. movff	fsr0hSave, FSR0H
  17.  
  18. ; Restore processor context and return
  19. movff	bsrSave, BSR
  20. movf	wSave, w, 0
  21. movff	statSave, STATUS
  22. retfie	0

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