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  • Build quality is good, but linked manual is wrong

    posted by lambition on 07/16/2015

    Impression:Good build quality.;

    Build quality of this product is good. However, circuit diagram in linked manual is incorrect.
    I did not use arduino library and wrote code only using datasheet of 74HC595 shift register and circuit diagram.

    LED did not work as I expected and took forever debugging and testing signals. What I found out is that circuit diagram was incorrect.

    Circuit diagram shows first register is for digits and second register is for segments. However, second register is actually digits and first is segment. Have to send digit data first and segment data after.
    Also, order of pins (bits) are reversed as well.

    Another thing to note is that this segment LED is common anode (sharing positive pin). So, signal sent to segments have to be inverted. (0 is on and 1 is off).
    This was not noted anywhere in the manual or item description.

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