The PCF8574 is a silicon CMOS circuit provides general purpose remote I/O expansion (an 8-bit quasi-bidirectional) for most microcontroller families via the two-line bidirectional bus (I2C-bus). In principle, such backpacks are built aorund PCF8574 (from NXP) which is a general purpose bidirectional 8 bit I/O port expander that uses the I2C protocol. Using the LCD backpack, desired data can be displayed on the LCD through the I2C bus. Hitachi’s HD44780 based 16×2 character LCD are very cheap and widely available, and is an essential part for any project that displays information. This allows connection to your Arduino (or other microcontroller) using only four channels. You can use them with LCD modules that have a HD44780 compatible interface with various screen sizes by attaching to the back of the LCD module.
Now a days, it is not necessary to buy an expensive I2C LCD for this task because readymade serial backpack modules for standard LCDs are available at reasonable rates. However, if you use an LCD module with I2C interface, you only need 2 lines to process the display information. To link a standard 16×2 LCD directly with the microcontroller, for instance Arduino, you would need atleast 6 I/O pins to talk to the LCD. I.e.Assume that you are moving towards a complex microcontroller project bundled with blinkers, beepers, and a display panel. Have no idea what a constructor is but surely it is great. If it doesn’t, the easiest thing to do in order to find the correct constructor is run the I2CLCDGuesser sketch fund hereįinally. If the constructor that you have found works, all is good. Remove any libraries named Liquid Crystal from the core libraries which came with the IDE at C:\Program Files (x86)\Arduino\libraries It should be installed in the sketchbook libraries which should be at C:\Users\yourName\Documents\Arduino\libraries The latest version (V1.2.1) of the F.Malpartida library is at Once you get it working, this is a fine, value, brick. Look out for the libraries, ans there are many, that look the same, but do not act the same. Took me hours/days to get it working, but with my details, you may have faster results.
I will order more!Ĭan’t make work with the manual provided (none). LiquidCrystal_I2C lcd(I2C_ADDR,En_pin,Rw_pin,Rs_pin,D4_pin,D5_pin,D6_pin,D7_pin,BACKLIGHT_PIN,POSITIVE) Involvement:Expert (understands the inner workings) - Ownership:1 week to 1 monthĪffordable. Then I just re-installed it again with his code, and doesn’t work either. I have tried the library he mentioned, and it didn’t work. I have spent more than 3 hours, and getting nothing.Īgain. Just made triple sure my lines are correctly connected.įunny thing, I found this info from the product site. LiquidCrystal_I2C lcd(0x27,16,2) // set the LCD address to 0x20 for a 16 chars and 2 line display LiquidCrystal_I2C lcd(0x38) // Set the LCD I2C address If the guess is correct, the constructor will show up
advance to the next guess as soon as possible Use with caution!ĭo not leave things with an incorrect guess for too long.
Good thing since it could damage the hardware. NOTE/WARNING: Guessing the i2c constructor is not really a you should get something like this: - Guess constructor for i2c LCD backpack
=>5, find the pin layout: download i2cLCDguesser open it with notpad it’s just an arduino sketch. =>4, find your device address using this sketch while opening your serial Monitor : for my Uno, connections are (sda - A4) (scl - A5) ī, incorrect address All I2C device have an address from 8-127 something mine is 0x27 Ĭ, incorrect pins layout, you need to remap your pin. if it works, you are good to go, but most likely it won’t work.Ī, wire connection is incorrect. =>2, unzip: LiquidCrystal_V1.2.1.zip delete or move the original LiquidCrystal and all other lcd library you got
This was a question, but I have figured it out from some great people here, so here It a quick tutorial showing you how to do it.