Looks li9ke it should work just fine. Bob Ammerman RAm Systems ----- Original Message ----- From: "Pic Dude" To: Sent: Friday, June 14, 2002 11:57 AM Subject: [PIC]: Component reduction... > Been trying hard to squeeze my PIC boost gauge (from some months > ago) into a round gauge enclosure, and that means elimination of > as many external parts as possible. So I'm looking at every > component and thinking of why I really need it. Converted the > circuit from 10 direct-driven LED's to 12 MUX'ed LED's (3x4 config) > and then this occurred to me last night... > > http://www.avn-tech.com/stuff/mux_no_transistors.jpg > > Not shown in the pic is that all LED cathodes are to the left. > Also, the dashed line represents the division between the main > board and the display board (yes, I need 2 round PCB's). > > I could possibly eliminate the driver transistors since I have > extra ports to generate enough current. The reason of tying the > lines together is that I can reduce the number of wires going > between the main board and the display board. > > I think I'm not violating any PIC rules here: > - I can keep the tied-together lines at the same logic-level by > keeping them on the same port. > - By multiplexing, only one set of 4 is on at any point in time, > so I'm within the port's total max current. > - Also within the chip's max current. > > BTW, I need the 16F872 since I need an A/D. Nothing smaller w/flash. > > I guess what I'm looking for is the experts' blessing on this. Is > there something wrong here that I am missing? Or shall I start > my PCB layout....? > > Thanks, > -Neil. > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body