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Controlling 2 LCDisplays with one Arduino...yes/no?

Discussion in 'Arduino' started by Rich D., May 4, 2017.

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  1. Rich D.

    Rich D. Member

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    I want to use one of the newer LCD character displays that has a generous 40 x 4 character screen. This is done using 2 controllers in effect, with two enable lines. Has anyone tried this with an arduino? I am not sure if you can define two separate LCD objects, and at the same time share the same data lines.

    I suppose I could if I bit-bang all the control signals, but that would be pretty tedious for both me and the microprocessor when we could both be doing better things.

    I am not sure I want to spend the $25 bucks to get this 40 x 4 display, a 20 x 4 would be good enough, but when is good enough ever good enough?

    Here is the Mouser link that has details of the part. This page has the link to the PDF specs from New Haven Displays. http://www.mouser.com/Search/Produc...virtualkey66010000virtualkey763-0440AZ-FL-YBW
     
  2. JimB

    JimB Super Moderator Most Helpful Member

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    I have done it with a PIC.
    I just used my normal LCD routines, but with two enable lines.
    I just wrote to LCD Lines 1 and 3 using Enable1, and lines 2 and 4 using Enable2.

    The hard part was finding enough memory for the display buffers.

    JimB
     
  3. Rich D.

    Rich D. Member

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    To answer my own question: YES.

    If you tie the write line (R/W) low, and do not define it, the Arduino software will operate them using a write only, so there is no worry that all LCDs will try to read back to the Arduino simultaneously.
    The software is able to handle more ...at least 4 LCDs, likely more, and the pin definitions can be the same or different as required.

    Thanks, self!
     

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