On Thursday 27 December 2012 20:44:26 Charles Steinkuehler did opine: > On 12/27/2012 4:50 PM, Gene Heskett wrote: > > Greetings; > > > > I have now spent several hours doing google searches, looking for a > > chip that would be the reverse of a max232, so I can power this ttl > > based sparkfun thing from what is available from the serial port. > > There appear to be hundreds of variations on how to get from 5 or > > 3.3 volt powered motherboards to a serial ports voltages, but > > nothing to reverse that short of find an old ball mouse at a flea > > market and stealing the chip out of it. > > There is no special chip for this other than standard voltage > regulators (or in many cases, a simple diode). > > In the old serial mouse days, the mouse driver would set some of the > serial port handshaking pins to known steady-state levels and use > those lines as a (low-current) power source to drive the serial > mouse's LEDs and micro-controller. > > There's a reasonable write-up on the basics at this website: > http://www.epanorama.net/circuits/rspower.html > Thanks Charles, bookmarked FFR.
> ...but there are lots of different ways to do this, depending on > exactly what you need to power and how much current it's drawing. Cheers, Gene -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) My web page: <http://coyoteden.dyndns-free.com:85/gene> is up! It's spelled Linux, but it's pronounced `Not Windows' It's spelled Windows, but it's pronounced `Aieeeeeeee!' -- Shannon Hendrix I was taught to respect my elders, but its getting harder and harder to find any... ------------------------------------------------------------------------------ Master HTML5, CSS3, ASP.NET, MVC, AJAX, Knockout.js, Web API and much more. Get web development skills now with LearnDevNow - 350+ hours of step-by-step video tutorials by Microsoft MVPs and experts. SALE $99.99 this month only -- learn more at: http://p.sf.net/sfu/learnmore_122812 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
