Does anyone use a single chip solution consisting of a single 8 pin microprocessor?
An Atmel atTiny13 is $1.40 in an 8 pin dip package. These chips power up nicely, require no external oscillator, and are easy to program. If you don't trust them, get two. Use one to drive the high side of the SSR relay and the other to drive the low side. The paranoid among us can take the drive signals from the chips and feed them back as inputs to the main processor. It would then check that the chips are in the no signal state prior to starting the charge pump. It wouldn't do to have a failure of the failsafe circuit be undetected. Ken ----- Original Message ----- From: "John Kasunich" <[EMAIL PROTECTED]> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Monday, April 28, 2008 9:11 PM Subject: Re: [Emc-users] Watchdogs > Greg Michalski wrote: > >> >> So in order to get my CNC4PC charge pump board to work correctly (it >> relies >> on a 12.5kHz constant signal) I am going to need to create it's own >> thread >> in addition to the servo thread and the base thread? I am thinking this >> is >> possible to do, are there any negatives to creating a third thread? > > Does it need _exactly_ 12.5 KHz, or a _minimum_ of 12.5KHz? My bet is > on the latter. In that case, you could put the charge pump in the base > thread. If your base period is 40uS or shorter, you will get 12.5 KHz > or more. > > I would try to avoid adding another thread - if the new thread is faster > than your base thread it could actually increase the jitter in your step > pulses, which is not something you want to do. > > Regards, > > John Kasunich > > ------------------------------------------------------------------------- > This SF.net email is sponsored by the 2008 JavaOne(SM) Conference > Don't miss this year's exciting event. There's still time to save $100. > Use priority code J8TL2D2. > http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
