On Wed, Nov 24, 2010 at 7:52 AM, Bob Axtell wrote: > The way _I_ do debugging on non-ICD2-capable PICs is to connect a piezo > beeper to an unused pin, and beep out in MORSE CODE the value of the ADC > while running. It can be difficult to have an unused pin for a 8-pin PIC (or 6-pin PIC). ;= -) Back in 2005 I was using PIC12F629/MPASM and I use a pin (used for LED) for debugging (to check the loop timing). The product is Series 31 Photoelectric Sensor. http://www.pepperl-fuchs.us/cps/rde/xchg/usa/hs.xsl/11235.htm?rdeCOQ=3DSID-= 7C0F893C-1C405864 The through-beam version is a bit tricky since the transmitting unit (simple, non-intelligent) and receiving unit are separated. A faster 8-pin PICs would make things a bit easier. --=20 Xiaofan --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .