Jai, look up http://www.melabs.com/resources/articles/ledart.htm The article refers to PBP, but you will get the drift of what needs to be done from the hardware viewpoint. Regards, Anand Dhuru ----- Original Message ----- From: "Jai Dhar" To: Sent: Monday, June 30, 2003 7:59 AM Subject: Re: [PIC]: 4 7-seg displays > This method is something that I actually just thought off after I fired off my > last email!!! Since my 7-seg's are common cathod, I would need some sort of > transistor between the common-cathod pin and ground, correct? What came to mind > was a n-channel MOSFET (low side switch). This seem like a reasonable approach? > BJT's might be more attractive since they are in smaller in through-hole form, > but are there any big differences in what I use?? > > Thanks, > > Jai > > Quoting Ishaan Dalal : > > > Something that has worked for me in the past is to use one driver (74LS47/48 > > or 4511/4513/4543) and connect its outputs (A...G) to all 4 segments in > > common. That takes up 4 pins of your port. Then you use the other 4 pins to > > drive transistors that source OR sink power from each of the 4 7-segs. > > That's another 4 pins. One port does it! > > > > > ---------------------------------------- > This mail sent through www.mywaterloo.ca > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > --- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.489 / Virus Database: 288 - Release Date: 10-Jun-03 -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu