This backpack will work with any вЂstandardвЂ™ character LCD, from 8Г—1 to 40Г—4 sizes! As long as they have a 16-pin single-line connection header at the top. For Arduino users, we provide a easy-to-use library that is backwards compatible with projects using the вЂ6 pinвЂ™ wiring. We wanted to make a вЂbackpackвЂ™ (add-on circuit) that would reduce the number of pins without a lot of expense.Д«y using simple i2c and SPI input/output expanders we have reduced the number of pins (only 2 pins are needed for i2c) while still making it easy to interface with the LCD. (or similar microcontroller) but find that the number of pins necessary to control the LCD can be restrictive, especially with ambitious projects. Character LCDs are common, and easy to get, available in tons of colors and sizes. LCDs are a fun and easy way to have your microcontroller project talk back to you. LCD backpacks reduce the number of pins needed to connect to an LCD. LiquidTWI library is attached to this post, also mirrored here: Of course, next on my to-do list is a proper animation library for character LCDs. What a sleek beautyвЂ¦ just watch the video. I fully gutted LiquidCrystal of all functions relating to digitalRead/digitalWrite, and made it 100% pure i2c. IвЂ™m sure C++ will allow a typedef alias for any libraries/sketches that have LiquidCrystal hard-coded into themвЂ¦ I just havenвЂ™t had a need yet. It just had to be вЂњforkedвЂќ to its own library.

I kept running into issues where Wire.h needed to be part of every program I use LiquidCrystal with. OK, so the next stepвЂ¦ package it up into something usable.

I could do animation on the screen once again, and it was smooth. I first made a proof of concept modification to the library to вЂњburstвЂќ all the вЂњLiquidCrystal::sendвЂќ bits instead of digitalWrite()вЂ™ing them out one at a time (read I2C, modify, writeвЂ¦ read, modify, writeвЂ¦ read, modify, writeвЂ¦ read, modify, write вЂ“ over 16 I2C commands for each single character). Often, the two go hand-in-hand рџ‰ДЄfter looking through the modified LiquidCrystal library for use with the i2c backpack and darn near crying when I saw all the faux digitalRead() and pinMode() being done on each transfer, I was bound and determined to never let that happen to another friendly Arduino user again. LiquidTWI: High-performance LCD library for I2C Backpack Module, FalconFour writes вЂ“

Adafruit i2c lcd proteus library