Dual led question

Discussion in 'The Projects Forum' started by u-will-neva-no, Sep 11, 2011.

  1. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
    Hi everyone, I have a short question based on dual (bi) dot matrix leds. My led dot matrix has 24 pins and has 2 leds (green and red) in each of the 64 segments. All i want to do is wire it so that one led color lights up. So what i have done is not to connect the red pins so that thr green lights up.

    Do I have to connect all pins on the led matrix to my IC (which is the Austriamicrosystems chip that produces the same function as the MAX chip).?

    Thanks!
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    You have given two manufacturer's names, Austriamicrosystems and Dallas/Maxim (actually, just implied the last) and mentioned that you have a dual (bi)-color dot matrix LED.

    We don't know which of their IC's you are talking about.
    We don't know if your LED matrix is common cathode, common anode, or if they are connected as cathode-to-anode and anode-to-cathode.

    Basically, with the information you've supplied, we can't give you an answer.

    Post links to the datasheets for your LED matrix, and the ICs that you are referring to.
     
  3. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
    I have the AS1107PL and my led matrix is common cathode. I forgot to mention that, sorry. The IC only works with common cathode so there is no issue regarding that. I will post the data sheet on thr next post.
     
  4. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
    Here are the images
     
  5. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The AS1106/AS1107 is an 8-digit 7-segment display driver, and you have an LED matrix, not a 7-segment display.

    I don't know how you're planning on connecting them up, but it's not going to work very well.
     
  6. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    So it does. It would have been easier and faster to answer your question if you had linked to the datasheets when I requested it.

    You will need one AS1106/AS1107 per digit, and you will need to connect the matrix as shown in the datasheet on page 16.

    And yes, you can just use the one color LED, leaving the pins for the anodes of the non-used LEDs disconnected.
     
    u-will-neva-no likes this.
  8. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
    Ah thats good then. I provided the IC circuut from the data sheet thinking that It would be quicker. In future I will attach the data sheet, sorry about that and thanks for replying!
     
  9. John P

    AAC Fanatic!

    Oct 14, 2008
    1,634
    224
    Anyway, the answer is--if you only want to drive one color, just ignore the pins that supply the other color. And with an array like that, there is no such thing as "common anode" or "common cathode". You drive it as a matrix, where the cathodes go to the appropriate pins of the IC and the anodes, likewise. You will have to figure out what to send to the IC to display any characters you want to see!

    Actually maybe it's better to ground the unused pins than just leave them floating. But no current will pass that way.
     
    u-will-neva-no likes this.
  10. u-will-neva-no

    Thread Starter Member

    Mar 22, 2011
    230
    2
    Thanks John P, I will do as you advised and ground the pins just as a safety measure.
     
Loading...