Hal wrote: > >Back in those days, there was a lot of activity in designing kludgey circuits >to "fix" metastability. I could usually find the flaw. It got boring after >a while. The classic was a circuit to detect metastability and reset the FF. >That reset signal would sometimes have runt pulses. >
My favorite online metastability page: _http://www.fpga-faq.com/FAQ_Pages/0017_Tell_me_about_metastables.htm_ (http://www.fpga-faq.com/FAQ_Pages/0017_Tell_me_about_metastables.htm) This page discusses a few of those "fixes" and why they don't work, along with some pointers to the relevant literature. There are also some nice real-time scope shots showing some of the various runt pulses that can occur: " " _http://www.fpga-faq.com/Images/meta_pic_1.jpg_ (http://www.fpga-faq.com/Images/meta_pic_1.jpg) " _http://www.fpga-faq.com/Images/meta_pic_2.jpg_ (http://www.fpga-faq.com/Images/meta_pic_2.jpg) " _http://www.fpga-faq.com/Images/meta_pic_3.jpg_ (http://www.fpga-faq.com/Images/meta_pic_3.jpg) " "These are far from just delayed outputs! The end result though "is still the same, systems that fail. But seeing these scope "pictures of the actual Q output might make you think about how "you measure metastability. " Brian **************BUY Indiana Jones and the Kingdom of the Crystal Skull on DVD today! (http://pr.atwola.com/promoclk/100000075x1209326865x1200539441/aol?redir=http://www.indianajones.com/site/index.html) _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.