HD 44780 with I2C converter library problem

Hello, I have very weird problem with my display (or something else). I have blue LCD 16x2 connected via I2C converter. Have tried various libraries but only one was “almost” working - popular LiquidCrystal_I2C by maroschwartz. I’ve set I2C pins adress scanned by I2C scanner as 0x3F, and set number of columns and rows. And after upload strange things happens - THE LCD DISPLAYS ONLY FIRST LETTER OF EVERY STRING. So instead of “Hello, world!” I have “H” in the first column of first row. What i discovered next is that the numbers displayed directly from variable are correct. I am also sure this is not problem with LCD because it works with another board with some old program using same configuration (HD44780 + I2C + Pro Mini),.

I’ve spend like three days trying different libraries, arduino boards, USB to TTL converters and set ups. the result is always the same! The only clue is I am using Windows 10.

HelloWorld.ino (420 Bytes)

Finally, I figured it out! The problem wasn't caused by the hardware or library. I'd searched web for alternative to Arduino IDE programs and I've found online editor codebender.com which finally uploaded my hello world sketch and it worked perfectly, so whole phrase appeared on the screen on my LCD.

I would give "Karma" to myself for this if I were able to do so. ;)

I've spend like three days trying different libraries, arduino boards, USB to TTL converters and set ups. the result is always the same!

I think you mean I2C adapters not USB to TTL converters.

You have discovered (the hard way) is that there is no standard design for these I2C adapters so each one requires a library that is designed for it, but all of the various libraries seem to have the same name.

Now that you know that your device works you might want to investigate the 'New LiquidCrystal' library which can deal with many of these adapters as well as with conventional (parallel interface) displays.


No, no, you are wrong, I've meant exactly what I wrote :) I was uploading programs by fake Prolific USB to TTL (pl2303hx) which became not supported and I had to deal with walkabout of this issue (installing old drivers). When I finally was able to upload my sketches, the LCD was still not working so I bought new USB to TTL.

Well, I will try this library again with codebender, but believe me or not, it was not working with Arduino IDE. The fact is I've been using same library that I've successfully used on July 2015 and it is not working anymore. Another fact is I copied library from my Arduino folder and uploaded it to codebender from where i uploaded hello world sketch to my board and it worked, so I am not sure if it was the issue with the compability of the library with I2C adapter :)


Same problem here and today i'll gonna try old versions IDE. With IDE published about June 2015 i had no problem, with the last IDE (1.6.6) the problem appears.

I'm using a YWRobot i2c interface for LCD (link to model and related library).

Another strange behaviour with the new ide: if a try a simple hello world sketch it shows only first char of each line. I f I try SerialDisplay (it write on display strings enterd on serial monitor) example sketched included in library all works fine.

I think is a good idea to write the problem to IDE developers.

The problem is already listed on IDE github: https://github.com/arduino/Arduino/issues/4142