This Application Note shows how the C505L can be used to control a Liquid Crystal Display. The example provided uses the C505L LCD controller and A/D Converter to implement a simple voltmeter. 1 Introduction..3 2 Theory of Liquid Crystal Displays3 2.1 Structure of Liquid Crystal Displays 3 2.2 Multiple Backplanes to Reduce the Pin Count..6 3 Control of LCDs .7 4 LCD Controller of the C505L..11 5 Connecting an LCD to the C505L.12 6 The Application14 6.1 Hardware and Connections ...14 6.2 Software Algorithms15 Appendix 17 A Main.c..17 B LCD.c ..19 C Putchar.c ..19 D LCD.h..21 E Reg505l.h .22