Hi Eric I've tried all sorts of things with this problem of unknown pin condition during PC start and stop and came to the personal conclusion that there is nothing short of a charge pump that I can be absolutely certain of.
The charge pump idea is that you have to have periodic changes to the pins in order for the external hardware to pull in or activate its output. I suppose, assuming that the pins of something like an m5i20 all change at the same time during startup and shutdown you could set a code across a pair or more that said if these are up and those down then the PC system is ready. HTH Rayh works like a charge pump out there. On Fri, 2008-04-04 at 09:42 -0400, Eric H. Johnson wrote: > Steve, > > How would an external pull up and pull down resisters work? What > differentiates the startup state from a controlled assertion of the output? > > Thanks, > Eric > > You can use external pull-up and pull-down resistors to set pin state. > I'm pretty sure that is the only way to set outputs the way you want during > early boot. You can also use a relay or charge pump in the E-Stop chain - > that should prevent anything from happening on the machine before EMC is > running. > > > > ------------------------------------------------------------------------- > Check out the new SourceForge.net Marketplace. > It's the best place to buy or sell services for > just about anything Open Source. > http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
