LCM BASIC TECH

The first LCDs were composed of only the LCD panel. This left the drive circuitry to the customer. More recent developments have combined the LCD panel with a PCB( printed circuit board) containing the drive LSI. This is known as an LCD module, which offers customers a more complete solution. There are two types of LCD modules: character and graphic. The character module is composed of 1 to 4 lines of 16 to 40 character blocks having 5 x 7 dots plus cursor. Each character block is addressed separately and can form alphanumeric characters and a limited number of symbols. Graphic modules provide users with a greater degree of flexibility. They are composed of pixels arranged in rows and columns. Each pixel can be addressed individually for text, graphics or any combination of the two. An LCD controller IC (intergrated circuit) is required to operate the graphic LCD. Some models feature the controller chip built into the module. See the Graphic Module Section for details. Tecdis dot matrix character LCD modules are offered in a variety of sizes and configurations. Character modules are organized in blocks of 5 x 7 dots. This allows them to display characters to 4 lines of 40 characters. Each model is STN (FSTN) fluid for enhanced viewing characteristics. Standard TN fluid is available, but is not recommended for new designs due to its limited contrast and viewing angle. EL or LED backlighting is an option for most models. Character modules contain a built-in HD44780 controller chip that allows the LCD module to receive data directly from a 4-bit or 8-bit microprocessor or microcontroller. The HD44780 has 192 character patterns in the character generator (CG) ROM. Also available is user-definable CG RAM, which allows the user to program up to 8 characters.