how to connect seven segment with PIC

Discussion in 'Embedded Systems and Microcontrollers' started by ect_09, Nov 1, 2014.

  1. ect_09

    Thread Starter Member

    May 6, 2012
    180
    1
    Hi,
    i have seven segment (3 segment connected together), i attached the image.
    please tell me how to interface with PIC18f452.
    doses it connect with a single port.
    please guide me.. IMAG0132.jpg IMAG0133.jpg
     
  2. ericgibbs

    Senior Member

    Jan 29, 2010
    2,499
    380
    hi,
    I count 28 pins on those 3 Digit LED displays, I would say that they are 3 individual digits.
    Do you have a datasheet or part number.?
    E
     
  3. MrChips

    Moderator

    Oct 2, 2009
    12,414
    3,353
    Brand, model number and data sheet would be required. You will need to know pin functions and configuration, common anode or common cathode.

    You can interface it with one 8-bit port, 4 bits for BCD decoder/driver and 3-bits for digit select.

    If you want to wire it directly without a decoder/driver, it will require two ports, 7 bits and 3 bits.
     
  4. RRITESH KAKKAR

    Senior Member

    Jun 29, 2010
    2,831
    89
    Hi its very simple and easy in few step.
    If you don't have any data sheet just use a cell or small battery with a ~220Ohm resistance.
    take a piece of paper or note book just note all pin on that book and test all pins with battery.
    do this and report.
     
    ericgibbs likes this.
  5. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,386
    1,605
    The display is an older Panasonic device, part number LN-536GAMG. (It's written on one of the parts in the picture.) This is an orange common anode seven segment display.

    To drive a common anode display you supply a positive drive to the common line and a negative sink to just the segments you wish to light. Of course a limiting resistor is needed.

    The basic scheme looks like so:

    [​IMG]

    The base drives (RA0, 1, 2, & 3) are normally high, set one only to turn a segment on.

    The segment drives (RB0-RB6) are also normally high, set each to turn some segments on.

    The transistors are needed as the segment drive will have to turn from 2 to 7 (or 8 for the decimal point) LEDs on at the same time, so this needs to supply a high current.


    Here's a link to someone's PIC project where they do something similar.
     
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