Check out those org statements. The first one says assemble the following >4 lines at address 0. The next one says assemble the following interrupt handler at location 4. Since the first org had more than 4 lines you are asking to overwrite the previous section. The trick is to put a jump after the nop to the label mainline and put all the code between the nop and the interrupt handler at mainline. -- View this message in context: http://www.nabble.com/-PIC--Overwriting-Previous-Address-Contents-t1826293.html#a4984037 Sent from the MicroControllers - PIC forum at Nabble.com. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist