Decoding to Hex for 7-seg Display

Discussion in 'General Electronics Chat' started by cldudley, Sep 25, 2010.

  1. cldudley

    Thread Starter New Member

    Oct 7, 2009
    11
    0
    Hi forum, I have a question for my new 8086 SBC project. I want to display the current values on the address and data bus when I am single-stepping the computer, but I really don't want to use a bunch of LEDs, I would rather have something like a 7-seg display to show the values in hex.

    I think what I am looking for are the TIL311 displays, as seen on Jameco here: http://www.jameco.com/webapp/wcs/st...amecoall&ddkey=http:StoreCatalogDrillDownView

    I really don't want to pay $15 per display, when I will need like 10 of them to decode all of the signals I want. Is there a cheaper/easier way to do this?
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,785
    945
    This would eliminate a lot of circuit building to interface standard LED Hex displays for display of a bus lines contents.

    Using the built in store, display support in the HEX display chip all you need to do is build a simple data buffer port, if your not already set up with a data port somewhere you might access.

    It would save lots of circuit building time and board room , that's about the only advantage I could see in using it. How much $ is a plain Jane Hex segmented display going for now-a-days? If the prices are comparable, this would be cheaper and less complicated.
     
  3. Markd77

    Senior Member

    Sep 7, 2009
    2,803
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  4. Markd77

    Senior Member

    Sep 7, 2009
    2,803
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    Failing that it would be easiest thing to do with a cheap micro. I think it could be done in about 30 instructions with a cheap PIC like the PIC16F505.
    Even with buying a programmer it would be cheaper than TIL311s.
    I'd be happy to write the code if you want to do it that way.
     
  5. sbombs

    Member

    Feb 26, 2010
    33
    0
    CD4511
    7447 does BCD - 7 Segment
    Dj Delorie of gEDA fame has his own http://www.delorie.com/electronics/bin2seven/
    I bet DJ makes his own electrons from scratch.

    But, I have to tell you that Binary to Hex conversion is very easily and quickly done visually. Even if you can't do math! Group the bits into groups of 4 bits. Write down, or memorize the table of

    0000 = 0
    0001 = 1
    0010 = 2
    etc
    etc
    1110 = E
    1111 = F

    example: 1011010111011010
    1011 0101 1101 1010
    b5da
     
  6. marshallf3

    Well-Known Member

    Jul 26, 2010
    2,358
    201
    4511 is just BCD - decimal, didn't there used to be a BCD to full hex chip?

    0 1 2 3 4 5 6 7 8 9 A b C d E F
     
  7. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
    Yes, the MC14495. Link to datasheet in post 3. It's most likely hard to find these days, but perfect for the job.
     
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