Using 14-pin LCD with 16-pin LCD Backpack??
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Using 14-pin LCD with 16-pin LCD Backpack??

by john3exonets on Sun Oct 21, 2012 7:39 pm

All,

Just got a number of I2C LCD Backpack's and found out they are looking for 16-pin LCDs....my are all 14-pin :( <Sarcasm>Conveniently, the backpack has no numbers on the interface pins</Sarcasm>, so you can tell which solder pad is for pin 1, and which one is for pin 14...so I can't even be sure I'm using the right pins. These LCDs work just fine with my Arduinos, so I'm thinking they should be able to work with the backpack...if I only knew what pins to use. Anyone know??

Thank you very much for your assistance :)
John
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Re: Using 14-pin LCD with 16-pin LCD Backpack??

by adafruit_support_bill on Mon Oct 22, 2012 5:59 am

The backpack is designed for standard HD44780 character LCDs. Aside from the 18-pin RGB variants, character LCDs are pretty universally 16 pin devices. Where did you find the 14-pin displays? If they do not use a HD44780 controller, they may not be compatible with the backpack library.

This data sheet shows the standard 16-bit pinout. The tutorial shows how the backpack attaches to a display.
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Re: Using 14-pin LCD with 16-pin LCD Backpack??

by john3exonets on Fri Nov 30, 2012 11:51 am

They are Optrex DMC16230 16 x 2 LCDs. They are HD44780 driven, or at least they respond correctly to the signals and work with the Arduino LCD library...I'm using several right now in some projects using a 4-pin bus. Here's a datasheet I found on the Internet (http://www.digchip.com/datasheets/parts ... 30-pdf.php) They are only 14-pin.

Thanks for your help! :)
John
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Re: Using 14-pin LCD with 16-pin LCD Backpack??

by adafruit on Fri Nov 30, 2012 12:22 pm

14 pin displays often just dont have a backlight - they'll work fine
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Re: Using 14-pin LCD with 16-pin LCD Backpack??

by adafruit_support_rick on Fri Nov 30, 2012 12:22 pm

The extra two pins are for the backlight. Your LCDs don't have backlights. Here's a picture of the backpack board layout, with pins 15 and 16 located. Just leave those empty and attach your LCD to pins 1-14.
i2cspilcd_pins.png
i2cspilcd_pins.png (47.23 KiB) Viewed 1288 times

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Re: Using 14-pin LCD with 16-pin LCD Backpack??

by john3exonets on Tue Dec 04, 2012 11:50 pm

Yep, that worked! Down to two pins to my Arduino now :) Thanks!
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