In the old days people used complex barrel switches for this sort of thing. I'd be thinking about hooking a PIC to it, and throwing transistors one way or another to short PGM1 and PGM0 to the proper leads. Sounds like a mess How 'bout two chips (samples are free from Maxim!) and one big power switch? I think I would stay away from this idea, and stick with one batttery voltage. What are you powering? --Lawrence ----- Original Message ----- From: "James Fitzsimons" To: Sent: Wednesday, January 23, 2002 10:51 PM Subject: Re: [PIC]: Circuit with PIC and Ni-MH > Hi all, > > Just thought I'd jump in on this Thread... > > Lawrence Lile wrote: > > I've just been working on battery chargers for a mowbot application. Been > > using NiMH batteries, and a MAX712/713 battery charger IC. Got a nice 2 > > amp charger working on a 2 amp-hour battery, pretty much straight off the > > app notes in the datasheet. > > I am in the middle of doing the very same thing, however I wanted to add a > rotary switch to my charger that would make the number of cells selectable > between 6 and 9. The thing is there are 4 points in the basic circuit that > need altering depending on the number of cells, these being R1, Rsense, PGM0 > and PGM1. Any suggestions on how I might alter all of these values by > turning one switch? > > Thanks for any suggestions, > kind regards, > James Fitzsimons > > -- > http://www.piclist.com hint: The PICList is archived three different > 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.