i've got my i2c backpacked LCD (PCF8574-based one from ebay, like the Sainsmart or YFRobot ones) working with my Mega2560r3 using the newLiquidCrystal library but does anyone know how to get them working with the LiquidCrystal_I2C library?
The reason I'd prefer the LiquidCrystal_I2C version is that there is a modified version that works with the ATtiny85 on the Playground by the author of TinyWireM, although I can't get it to work either.
If I could get it to work on the Mega, I think I could get it to work on the Tiny, although I'm not convinced TinyWireM actually works with IDE 1.0+ anyway, I've already wasted 2 days fighting with it!
It does seem odd that there are so many LiquidCrystal libraries floating about and pretty much the only one that works with the HD44780 with or without I2C is newLiquidCrystal! I had the same problem with the Raspberry Pi, I modified the Adafruit library to work with that (no I2C) after trying about five different ones.