Hello, all.
I have this strange intreface attached to my lcd. I suspect it's a simple mux, but I have no clue how it's wired. I've some pictures below. any insight would help.
According to the datasheet on the chip, and seeing the I2C pins on the other side, this appears to be a I2C 8-bit port expander chip, and I'm guestimating the chip is converting serial (I2C) to parallel output (8-bit, to the LCD I imagine).. this is a link to the datasheet I found on the chip: http://www.nxp.com/documents/data_sheet/PCF8574.pdf
Hope this helps!
Go on. You have a regular I2C interface attached to your LCD.
These are so common, that I cannot believe that you have never seen one on Ebay, Aliexpress, DX.com, ...
From your photo, it looks as if the I2C address will be 0x27. But it is safer to run the i2c sniffer sketch to get the correct constructor for the LiquidCrystal_I2C library.
David.