4 Bit Bcd Input To 7 Segments Displays?

Discussion in 'The Projects Forum' started by thanosgen, Jan 15, 2007.

  1. thanosgen

    Thread Starter Member

    Jan 15, 2007
    11
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    Be drawn and materialise in rasters a reasonable circuit that would appear in 7 seagments displays sectors the digits of hex system of numeration. the numbers that i want to see will be appearred as in the following form:


    6 A B C D E F

    Code the digits it will be given as BCD with Dip-switch

    CAN HELP ME ΟR IS DIFFICULT?????

    p.m. with multiplexter can i do it??????

    i need something like this
    [​IMG]

    i give the 1111 and i want to see the F etc
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Can't be done - BCD stands for Binary-Coded Decimal. It is only meant to represent the values 0 to 9. Four bits will give the values of 0 to f, but a 7 segment display can only show 0 to 9, plus meaningless junk. Your illustration shows a 7 segment display.

    You will need an alphanumeric display plus additional circuitry to display the values of 0 to f.
     
  3. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Beenthere is 100% correct. 4-bit BCD is only capable of representing the digits 0 through 9.

    On the other hand, if you have a 4-bit binary value, you can use a microcontroller to produce a set of characters using a 7-segment display that comes close to the 5 additional characters you would require.

    1010 A (uppercase A)
    1011 b (lowercase B)
    1100 c (lowercase C)
    1101 d (lowercase D)
    1110 E (uppercase E)
    1111 F (uppercase F)

    hgmjr
     
  4. thanosgen

    Thread Starter Member

    Jan 15, 2007
    11
    0
    how i do it?you have any circut or microcontroller?
     
  5. mrmeval

    Distinguished Member

    Jun 30, 2006
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  6. thanosgen

    Thread Starter Member

    Jan 15, 2007
    11
    0
    thanks my friend but this circuit have very much gates.i need something to put in raster.from 1 to 3 chips.
     
  7. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    When you use the term "raster", do you perhaps mean multiplex such that one set of 7-segment drive electronics is shared among several 7-segment displays?

    hgmjr
     
  8. thanosgen

    Thread Starter Member

    Jan 15, 2007
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    0
  9. hgmjr

    Moderator

    Jan 28, 2005
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    So when you use the term "raster", are you referring to the type of prototyping board onto which you are mounting your chips?

    hgmjr
     
  10. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    One of those happy accidents led me to discover the MC14489. It will drive up to 5 displays and cover the full range of hexidecimal characters. It needs more than a dip switch input, though. Just google mc14489 for a data sheet.
     
  11. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    I think such accidents are termed "serendipitous".

    hgmjr
     
  12. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    What is needed is not a BCD-to-seven-segment driver, but rather a Hex-to-seven-segment driver. The [SIZE=-1]MC14489 cited by Beenthere is one example. So too are the 4N54, the EDE707, and for more modern applications the MAX6950/MAX6951.
    [/SIZE]
     
  13. lightingman

    Senior Member

    Apr 19, 2007
    374
    22
    OH HERE I GO AGAIN !!!!Yes you can do it "with an EPROM and a ULN2003"... Something small can do it, like a 2732 (27C32). Have you the means to program one ??, if so I will give you the code.If not just P.M. me your details and I will program and send you one (with schematics)... Daniel.
     
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