Not sure if this is the right place to ask. I have trouble making gpsim accept a statement like: stimulus sqw period 1000 name pulse1 end but the equivalent: stimulus asy 500 500 period 500 port porta 3 end works. However it does not produce the right result. The pin where it is attached does not toggle. Is this a known bug ? Peter -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics