2-wire LCD interface using PIC16CF84

  
Inside:
Repository
Alphanumeric LCD displays have become very popular for microcontroller applications because they can add a lot to a project in a variety of different ways. A text message giving the user instructions as well as feedback can make the application seem much more `professional` and easy to use. I like to use LCD`s to help debug applications, with breakpoints set to display
2-wire LCD interface using PIC16CF84 - schematic

variable and I/O conditions and they are a lot cheaper than using a microcontroller emulator. To top it off, surplus LCD`s can be found for a dollar or less. The most popular LCD interface is the Hitachi 44780 based LCD controller chip which provides a fairly easy to work with interface and low power consumption. The major drawback of the interface is the perceived complexity of working with the interface. This perception has been promoted by the lack of good (i. e. well translated) and accurate datasheets and web site information. Often the biggest stumbling block to using alphanumeric LCD displays is the number of pins required to control them. For the Hitachi 44780, twelve pins are required from the microcontroller to interface to the display for it to work in eight bit mode. For many smaller microcontrollers, twelve pins are not available or will be better served in the application. To be fair, this can be reduced to six by using the 44780`s "Four Bit" mode, but this can still be more than acceptable for most applications. A popular solution that only requires one pin from the microcontroller to the LCD is the use of "Serial LCD Interfaces" to the data and signals necessary for the Hitachi 44780 controllers. Many of these products (such as the SLI-OEM) are excellent and can provide useful product interface and debugging information. The only drawback to them is the need for properly timed NRZ serial data which may be...



Leave Comment

characters left:

New Circuits

.