By the way no latch or FF is "metastable-proof". All you can hope for is = to make the probability of metastability as small as desired (but not = zero).=20 Art Porter Agilent Technologies =20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Peterson, James F (FL51) Sent: Monday, January 09, 2006 12:44 PM To: tbiggs@xxxxxxxxxxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: METASTABILITY A quick read of the app-note shows the "metastable-proof flip-flop" as a double flip-flop (or latch) circuit., so it's a nifty little metastable-proof circuit (which is done all the time), not a metastable-proof flip-flop.=20 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Tom Biggs Sent: Monday, January 09, 2006 1:52 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: METASTABILITY -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of Mike Greim "However fast we make the device, =3D3D there is always the possibility = =3D that the input events will be so close =3D3D together that it cannot detect = =3D which one happened first. It is therefore =3D3D logically impossible to build = a perfectly metastable-proof flip-flop." ---------------- Actually, that's not true. Philips used to sell PLDs with = metastable-proof flip-flop. I think they sold their PLD line to Xilinx, but I haven't heard of these parts since. I found an apnote describing them: http://noel.feld.cvut.cz/hw/philips/acrobat/8175.pdf ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu