pcf8574-lcd-demo.c is example C code how to drive a standard HD44870 character LCD display over a I2C-connected PCF8574-based backpack module. Tested on a Raspberry Pi 3.

Remaining code is a set of LCD programs that drive a mini-LCD type AQM0802 over the I2C bus of embedded systems. This includes popular devices like the BeagleBone Black, or the Raspberry Pi. The C code is based on a previous embedded C library for HD44780-based character LCD.

The AQM0802 2x8 character LCD is a downsized module that fits the scale of credit-card-sized boards, and can provide output of critical paramaters, such as the current WiFi DHCP address assignment.

Beaglebone Black example, using a prototype cape:

See also http://blog.fm4dd.com/?p=896

Interfacing the AQM0802 LCD display with a Raspberry Pi: