Chapter 5: LCD Modules

Overview

Blinking an LED is fine, as far as it goes, but it limits our communications opportunity with the outside world. If users are not to learn Morse code, a text-based message display expands our communications horizon greatly. Liquid Crystal Displays have become the display of choice for PIC output for good reasons; they are relatively inexpensive, have built-in support in MBasic and are available in a variety of sizes.

We'll deal exclusively with LCD modules supported by MBasic. An LCD module includes both the display and a controller board, as shown in Figure 5-1. Don't buy inexpensive LCD displays sold by some surplus stores without the controller board they are not compatible with MBasic's LCD functions. Almost universally, LCD modules use an Hitachi HD44780 controller/driver chip, or a derivative chip compatible with the HD44780 command set, such as Samsung's KS0066 or Epson/ Seiko's SED1278. (An HD44780 only supports a 16-character display, but with auxiliary chips will control up to an 80-character display.)

Figure 5-1: Main LCD module elements.

The particular display we'll use in our experiments is a Tianma TM162YBC6, 2-line, 16 characters per line display, super twisted nematic technology with LED backlighting, available from Basic Micro, as shown in Figure 5-2. However, almost any LCD module may be substituted for this display with little or no modifications to the hardware or software developed in this chapter.

Figure 5-2: TM162YBC6 LCD display.

The TM162YBC6's controller chip is a KS0066, U1 in Figure 5-3. In this product, the KS0066...