I am using a 16x2 LCD and have it connected with MCP23017 16-bit IO port expander. To display message to the LCD, I am using Adafruit LCD library. They also have a test python code to get it working with MCP23017. I have changed the pin according to the connections I have made but it seems to be displaying only blocks in the first row of the LCD. I tried different pins, but I can't get it to work.
Adafruit library: https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/tree/master/Adafruit_CharLCD (Here I am using LCD_MCP230XX_test.py file to test my setup).
Is there something or some configuration I am missing?