I am using a PIC18F1320 with the MPLAB compiler. I wrote the code, and while testing it I get a set of outputs with the oscilloscope, but when i disconnect the oscilloscope, the outputs are different. For example, I read in a byte over the serial port and compare it with a variable. If it matches then I light an LED. With the oscilloscope connected the LED never lights, without it it does. I am using the internal oscillator of the PIC. Could it be that the oscillation times change because of the oscilloscope? Please help me understand this. Thanks Nikhil -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist