Post by thread:[OT]: LCD 14-pin 2x7 pinout ?

Hi, I have a standard ascii LCD display with two lines, backlit etc, with the 14 pin 2x7 connector (for cables). The LCD board has pins 1 and 14 marked. This is not very usefull since I do not know for sure whether the pin order is: A) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 or B) 1 8 2 9 3 10 4 11 5 12 6 13 7 14 Notice how pins 1 and 14 are in the same position in both cases ;-(. No I cannot ask the manufacturer, I bought these in a shop. If any1 can shed some light on this, please do, tia, Peter PS: Is there a way to find out by measuring ? I tried comparative measurement vs. gnd etc but nothing conclusive came of it. The controller is epoxy splotch chip on board type so I can't check wires to pins. -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

On Fri, 19 Oct 2001, Peter L. Peres wrote: > I have a standard ascii LCD display with two lines, backlit etc, with the > 14 pin 2x7 connector (for cables). The LCD board has pins 1 and 14 marked. > This is not very usefull since I do not know for sure whether the pin > order is: C) None of the above. Viewed from the back it's like this: 13 14 11 12 9 10 7 8 5 6 3 4 1 2 http://www.doc.ic.ac.uk/~ih/doc/lcd/interfac.html is where I found a diagram, among other places. I've verified it, yes. Dale -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads

At 11:42 PM 10/19/01 +0200, Peter L. Peres wrote: >Hi, > >I have a standard ascii LCD display with two lines, backlit etc, with the >14 pin 2x7 connector (for cables). The LCD board has pins 1 and 14 marked. >This is not very usefull since I do not know for sure whether the pin >order is: > >A) >1 2 >3 4 >5 6 >7 8 >9 10 >11 12 >13 14 Standard dual row headers use the pin order in (A) above. dwayne Dwayne Reid <spam_OUTdwaynerTakeThisOuTplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 17 years of Engineering Innovation (1984 - 2001) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- 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

Dwayne Reid said: > > > >A) > >1 2 > >3 4 > >5 6 > >7 8 > >9 10 > >11 12 > >13 14 > > Standard dual row headers use the pin order in (A) above. > While it is true that the standard pin identification for a dual row header is as shown above, it is NOT the proper order when the pins exit from the BACK of the board, as they do on every LCD module that *I* have ever run across. Because the LCD header is always coming out the BACK of the LCD board, you can easily get confused when using a standard ICD cable to connect the LCD to a standard ICD header. The pin numbering gets exchanged, and if you are not aware of this, then you can easily mess up the wiring on your PIC board. The problem occurs because one of the headers (LCD) is actually mirror-imaged since it comes out the BACK of the LCD board. If the PIC board ALSO had it's header coming off the BOTTOM of it's board, then all would be OK. But the PIC board normally has the header on the TOP of the board. Viewed from the BACK side of the LCD board, which is the side where the pins stick out, it's like this: 13 14 11 12 9 10 7 8 5 6 3 4 1 2 * or, if rotated it can look like 1 3 5 7 9 11 13 2 4 6 8 10 12 14 * or * 2 1 4 3 6 5 8 7 10 9 12 11 14 13 or * 2 4 6 8 10 12 14 1 3 5 7 9 11 13 You will notice the (*) I placed next to pin (2) in each of these diagrams. THAT is the pin that pin (1) of the IDC CABLE connects to. This is a very important fact to take note of, because most likely that IDC cable will then connect to an IDC header on the board with the PIC, and THAT will have its pins sticking up from the TOP of the PIC board. The net result is that the pins end up getting switched around as follows, when using a standard IDC cable: LCD Header IDC CABLE PIC IDC header LCD FUNCTION 1 2 2 Vss (Gnd) 2 1 1 Vdd (+5) 3 4 4 Vo cobtrast adj. 4 3 3 RS 5 6 6 R/W 6 5 5 E 7 8 8 DB0 8 7 7 DB1 9 10 10 DB2 10 9 9 DB3 11 12 12 DB4 12 11 11 DB5 13 14 14 DB6 14 13 13 DB7 ********* What can you do if you have already messed up by having your PIC board wired up the wrong way? Use TWO identical IDC cables. Connect them together by using two 7 pin rows of header pins, or if you don't have that handy, then insert short lengths of snipped resistor leads or #20 bare single strand wire into all 14 pins of one cable end, and then plug the other cable into the one with the wire pieces. Insert the two cables so that the side with pins 1&2 plugs into the other cable's side that has pins 1&2. This effectively re-routes the wires so that LCD header pin 1 goes to PIC board header pin 1, and the same with all the other wires. Fr. Thomas McGahee {Original Message removed}

At 04:58 PM 10/20/01 -0400, Thomas McGahee wrote: >Dwayne Reid said: > > > > > >A) > > >1 2 > > >3 4 > > >5 6 > > >7 8 > > >9 10 > > >11 12 > > >13 14 > > > > Standard dual row headers use the pin order in (A) above. > > > >While it is true that the standard pin identification >for a dual row header is as shown above, it is NOT the >proper order when the pins exit from the BACK of the board, >as they do on every LCD module that *I* have ever run across. I agree with what you wrote but you are not answering the original question: do the pin numbers increment horizontally (like above) or vertically. I assumed (from past postings) that Peter would take any mirror problems into account because he already knows where pins 1 and 14 are on the display. I don't mean to be confrontational - please accept my apologies if it comes across that way. Peter asked which of two possible pin numbering schemes was correct given that he knew where pins 1 and 14 were. The diagram above is correct, given his location of those pins. dwayne Dwayne Reid <.....dwaynerKILLspam@spam@planet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax Celebrating 17 years of Engineering Innovation (1984 - 2001) * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Do NOT send unsolicited commercial email to this email address. This message neither grants consent to receive unsolicited commercial email nor is intended to solicit commercial email. -- 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