encoder 4bit 2 hex

Discussion in 'Homework Help' started by GALAS, Jan 8, 2007.

  1. GALAS

    Thread Starter New Member

    Jan 8, 2007
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    hi mates , i am new here and i have a little questions ...

    i want to make on breadboard a logic circuit which shows on a 7 segment display
    the hexademic. and the hexademic will be gived with BCD and Dip-switcth.. And it will be done with help off multiplects and -demu..

    i search it and ,i think that i will use 74ls47 , but this will show me from 0 to 7 , the others 9,10,a,b,c d,e,f?
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  2. beenthere

    Retired Moderator

    Apr 20, 2004
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    Hi,

    The 74LS47 is a BCD-to-7 segment driver. It will drive a display to show the numerals 0 to 9. Even if the ic could accept the full hexidecimal input of 0 to 15, the display is not made to show A, B, C, D, E or F. You can get liquid crystal displays that will show alphanumeric characters, but they need to be driven by much more elaborate circuitry.

    You mention that you're giving a BCD input - why are you trying to show values beyond 9? Binary coded decimal implies only values of 0 - 9.
     
  3. GALAS

    Thread Starter New Member

    Jan 8, 2007
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    The point is that i want to show me A,B,C,D e.t.c .. and i want an idea to do that ...
     
  4. rootboy

    Member

    Jan 4, 2007
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  5. GALAS

    Thread Starter New Member

    Jan 8, 2007
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  6. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    That's like wanting a Toyota to compete in a drag race. The 7447 is built to drive a seven segment display, which can only show the numerals 0 through 9.

    There are alphanumeric displays - Luminex makes several - that will show letters and numerals.
     
  7. GALAS

    Thread Starter New Member

    Jan 8, 2007
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    there'isn't an another way to show A,BC with 7447 ?with buffer ?
     
  8. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Please get the data sheet for a 7447 and see how it works. It does have outputs beyond 9, but nothing that will display a - f. Look at the data sheet for an alphanumeric display. It may suggest the driver to let it dosplay 0 - 9 and a - f.
     
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