The 16F628 data sheet indicates that when you use the low voltage in-circuit programming mode pin RB4 the interrupt on pin change feature is disabled. In people's experience, is it still safe to use the "interrupt on pin change" feature of the other 3 pins (RB5-7?) I have not used this feature much and recall posts off and on referring to it being a little sensitive to some configurations. Thanks, Tim -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu