On Fri, 20 Apr 2012, gene heskett wrote: > Date: Fri, 20 Apr 2012 17:36:29 -0400 > From: gene heskett <[email protected]> > Reply-To: "Enhanced Machine Controller (EMC)" > <[email protected]> > To: [email protected] > Subject: Re: [Emc-users] Relay driver not working > > On Friday, April 20, 2012 05:32:42 PM Dave Caroline did opine: > >>> It may be safe to ground the left end of that 220 ohm resistor, but >>> I'd be tempted to use a 1k resistor as additional current limiting. >> >> NONO this user has already killed a mesa card >> > If a 1k resistor to ground can kill a Mesa card, I'll buy the beer. That > would be, with the far end of the resistor tied either to 5 volts or to > ground, a half a milliamp current flow. I might start checking things at > 10 mills or more, but some of the buffer chips in use today can source or > sink 24 mills. Half a milliamp s/b a total non-issue. >> >> Dave Caroline >> >> ------------------------------------------------------------------------
All of our FPGA cards can safely sink 24 mA (and source 24 ma from 3.3V) Damaged cards are usually from applying voltages in excess of 5.5V (Spartan 2) or ~8V (Spartan3 and 6 with series bus switches for 5V tolerance) A dozen or so shorted I/O lines is unlikely to cause FPGA damage (ask me how I know) ------------------------------------------------------------------------------ For Developers, A Lot Can Happen In A Second. Boundary is the first to Know...and Tell You. Monitor Your Applications in Ultra-Fine Resolution. Try it FREE! http://p.sf.net/sfu/Boundary-d2dvs2 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
