----- Original Message ----- From: "Jan-Erik Soderholm" To: "Microcontroller discussion list - Public." Sent: Sunday, November 01, 2009 6:15 PM Subject: Re: [PIC] Any issues with running PICs from -5V supply ? > Peter Onion wrote: >> Resent with a TAG this time... >> >> I'm building a PIC circuit to interface to a very old computer that uses >> 0v for "1" and -10V for "0". >> (http://www.youtube.com/watch?v=8EKBNfm5B4U) >> >> It will make for simpler interface circuits if I run the PIC from 0V and >> -5V. (I.E. 0V on Vcc pins and -5V on Gnd pins). >> >> Are there any issues with doing this ? >> >> PeterO >> >> > > All voltages are rellative. > > The PIC doesn't "know" that what it sees > as "5V" is called by you as "0V". > > You could use 15V as "GND" and 20V as "5V" as > long as you do not do anything else "funny" with > your interfaces... Yes, I agree, but be very carefull with measuring equipment such as an oscilloscope. A ground error is easy made.. I should prefer read voltage translation. It is not that difficult. Jo > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist -------------------------------------------------------------------------------- Geen virus gevonden in het binnenkomende-bericht. Gecontroleerd door AVG - www.avg.com Versie: 8.5.423 / Virusdatabase: 270.14.43/2474 - datum van uitgifte: 11/01/09 07:38:00 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist