At 2002-08-28 23:58 -0800, Balekai, Krishna (IE03x) wrote: >Hi Aparna >The cable combination which you have mentioned is having 7 wires means it is >having 4X3 or 3X4 matrix for 12 keys. It means there are 4 scan lines and 3 >return lines or 3 scan lines and 4 return lines. There is no power wire >involved into that. Hence you have to switch on the circuit and check the >wires using oscilloscope. If you get transitions between 0 to vcc on three >lines means there are 3 scan lines and if you get transitions on 4 wires >means there are 4 scan lines. These scan lines must be generated from the >processor itself or there must be some keyboard controller on it. >Regards, >Girish R. Ghanekar
When assuming this organization (that I think is the most likely), consider that each key may contain a diode in series. Greetings, Jaap >-----Original Message----- >Sent: Thursday, 29 August 2002 12:20 PM >To: Multiple recipients of list CHIPDIR-L > > >Hello, > >I have a circuit for which I am doing some reverse engineering. > >There is a wire link to the LCD keypad. the keypad has 12 buttons on it. >namely 1,2,3,4,5,6,7,8,9,0,#,* >the wire has 7 wires one for power and apparently the rest of the 6 wires >represent the 12 keys. > >I wanted to know is there any standard combination for the keys. I cannot >apply power to check it out as I have to be careful not to blow the circuit. > >Can anyone help? How can I check? > >Regards, > Aparna > > >-- >Author: aparna > INET: [EMAIL PROTECTED] > >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 >San Diego, California -- Public Internet access / Mailing Lists >-------------------------------------------------------------------- >To REMOVE yourself from this mailing list, send an E-Mail message >to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in >the message BODY, include a line containing: UNSUB CHIPDIR-L >(or the name of mailing list you want to be removed from). You may >also send the HELP command for other information (like subscribing). >-- >Author: Balekai, Krishna (IE03x) > INET: [EMAIL PROTECTED] > >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 >San Diego, California -- Public Internet access / Mailing Lists >-------------------------------------------------------------------- >To REMOVE yourself from this mailing list, send an E-Mail message >to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in >the message BODY, include a line containing: UNSUB CHIPDIR-L >(or the name of mailing list you want to be removed from). You may >also send the HELP command for other information (like subscribing). -- Author: Jaap van Ganswijk INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
