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Driving two character LCDs in parallel

Posted on Tuesday, March 27th, 2012 in Development by DP

Abdullah explored the idea of driving two character LCDs in parallel. When he couldn’t find any information about this online, he decided to try it out himself.

Then I thought about it and I gave it a go. The result is positive! However, there is a gotcha; if you are using LCDs from different manufacturers or different types, the contrast setting might differ, as it did in my example. In order to overcome this, I would suggest putting two potentiometers in your board to adjust the contrasts individually. And don’t forget, you are using one more LCD, meaning more back light current. If you are using a 7805 without a heat-sink, you should re-calculate your thermal values.

This entry was posted on Tuesday, March 27th, 2012 at 9:00 pm and is filed under Development. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

2 Responses to “Driving two character LCDs in parallel”

  1. dccharacter says:

    Guys tested better idea on roboforum.ru: if you put all the lines but ENABLE in parallel, you can drive as many LCDs as you want by 10+N MCU pins (where N is number of displays, or 6+N – depending on mode 8 bits or 4 bits). Enable in this case just acts as chip select.

  2. Bill says:

    Using two LCDs sharing all but enable lines works great. Good work-around when Arduino 440 driver won’t work on a 4×40 display.

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