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I am looking at ordering this lcd https://www.sparkfun.com/products/255, however when looking at the picture it seems that there are some extra pins on the right side not described in the hd4470 datasheet. I was hoping someone could explain their use to me. Here is the picture enter image description here

I would assume that the LCD would act normally if I left these pins unconnected, but please correct me if i am wrong.

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By looking in the datasheet I can see this:

enter image description here

and

enter image description here

So they are the same as pins 15 and 16. Leave them not connected and use only pins 15 and 16.

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  • \$\begingroup\$ What about the 4 other pins next to A and K \$\endgroup\$ – popgalop Apr 30 '14 at 20:18
  • \$\begingroup\$ @popgalop A and K are 2 pins each, so only 2 pins left. They're probably the same A and K. Use a continuity tester or ohmeter to get an idea. Anyway, leaving them not connected wouldn't do any harm. \$\endgroup\$ – Cornelius Apr 30 '14 at 20:20
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The HD44780 protocol only requires a maximum of 14 pins, usually found either along the long edge in a single row or on one of the short edges in a double row. There may be 16 instead, in which case the extra 2 are for the LED backlight. No other connections to the module should be required.

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