Ah, but here is the rub: What do you do about voltage management with these super-caps? Not a trivial question. I have tested products designed elsewhere that had serious brownout problems with these super-caps. The cap will slowly bleed down to a point where the processor will not work correctly, the processor hangs or starts impersonating Napoleon, and the super-cap never bleeds off enough to actually reset the processor. It can literally be days before the processor resets. Meanwhile the LCD display is covered with chicken tracks. This was, of course, not in a PIC, and not with the handy brownout protection feature included in most modern PICs, and also not designed by any reputable PIClister (or me either). I would expect that watchdog and brownout protection would be a minimum requirement, but I still worry about partial reset when there is 3-4 volts on the PIC between power-ups. Anyone who has experienced partial reset in a PIC will now believe in ghosts, fairly tales, and goblins because those are the creatures that inhabit the PIC's brain after a partial reset instead of carefully crafted ASM code. It certainly does not act in a deterministic manner nor obeys it's software whatsoever. Quite dangerous if the PIC is hooked up to, say, a motor spinning sharp blades or a high temperature heating element. Have other people had power management issues with super-caps and PICs? -- Lawrence Lile Jake Anderson Sent by: pic microcontroller discussion list 02/08/2004 10:02 PM Please respond to pic microcontroller discussion list To: PICLIST@MITVMA.MIT.EDU cc: Subject: Re: [EE:] Post battery pull runtime put the cap on the battery side then set a battery monitoring thingie up on an interupt pin, or poll it. hows that work out for you? > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of James Nick Sears > Sent: Monday, 9 February 2004 8:59 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE:] Post battery pull runtime > > > Check out the Digikey catalog pages 728-729: > http://dkc3.digikey.com/PDF/T041/0728.pdf > http://dkc3.digikey.com/PDF/T041/0729.pdf > > Nick > > ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body