Mike, There is no software anywhere that can substitute for a hardware brownout reset circuit. The reason is, a brownout condition can make the processor execute random or undefined instructions, or load random, undefined numbers into the program counter. This essentially makes the processor "go insane", and the cleverly written software BOR routine doesn't work any better than no routine at all. I think BOR is as basic to microprocessor hardware design as a cord, power supply, and case. There. Now I feel better. I deal with this all the time in consumer products. We get them back in the lab, and test them, and lo and behold, they "go nuts" when you turn the voltage from 120V to about 60V, or put them on a brownout machine (plans are here): http://members.socket.net/~llile/acad1.htm Similar thing happens with battery operated equipment when the battery gets low. The suppliers then have to add a BOR circuit, which belonged there in the first place. The symptoms are: LCD displays chicken tracks, motors come on and stay on, controls lock up, consumers get mad and return your product. You can prevent this problem for about US$0.03-0.25. Cheap insurance. Here's a link to AN522 that explains it all: http://www.microchip.com/0/appnote/category/16c5x/00522/index.htm ----- Original Message ----- From: "Evans Michael E Maj ACC/XPPI" To: Sent: Monday, July 30, 2001 12:19 PM Subject: Re: [PIC]: 12C508 BOR > I'm working on a project involving the 12C509A which would benefit from the > BOR watchdog algorithm mentioned below by Peter Peres. I can reinvent this > wheel if required, but would later be stopped before its too late. Can > someone elaborate? Peter? > > Cheers > Mike > > -----Original Message----- > From: Lawrence Lile [mailto:llile@toastmaster.com] > Sent: Friday, July 27, 2001 9:37 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [PIC]: 12C508 BOR > > > You can make a cheap and dirty brownout reset for a 12C508 (or anything > else) with a ala' App note AN522 figure 7. I use these on a steam iron > control, and the parts cost is near US$0.03 in volume. Pretty hard to beat. > > It's not a precise brownout circuit, but my tests have shown it to work > reliably. > > > --Lawrence > > ----- Original Message ----- > From: "Peter L. Peres" > To: > Sent: Friday, July 27, 2001 6:01 AM > > > > >- The 12C508A is about 80 cents, but requires external BOR, but has int. > > >clock. > > > > In my experience the watchdog in a 12C508A can substitute for a missing > > BOR if you apply some continuous self-checking algorythm (cpu exercizer > > etc). > > > > Peter > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu