CP316: Microprocessor Systems and Interfacing

Liquid Crystal Display (LCD) Prelab

The objectives for the LCD lab are:

• to use timer0 as an interrupt based timer to provide appropriate delays for the operation of the LCD
• to initialize data strings in program memory and retrieve them for display to the LCD
• to initialize the LCD appropriately
• to write a program to demonstrate simple output to the LCD
• to write a program to demonstrate the use of the LCD buffer

You will first observe the LCD output when the LCD is not initialized.  Then you will initialize the LCD with the requested characteristics.  Note: the initialization is the critical point in the lab. 

Prelab Deliverables:

1. Construct a program that puts out a tick as a high priority interrupt based on timer0. The interrupt service routine should toggle the alive LED on the board. The mainline routine for this program would  initialize the standard ports and then the routine should go into an infinite loop. The tick interval is not important for the prelab but you should know what it is, how to measure it, and how to modify it to suit specific applications. This should be a simple modification of Question 6 from the previous lab. Come to the lab with this base program completely working.
   
   
2. In preparation for the lab, you should

• have the structure for the required programs established, i.e. how do you break up the tasks to facilitate reusability? As this code will be used for subsequent labs and the project, spending time on a good modular design will pay off.
• have the routine(s) to initialize the LCD and ports required by the LCD written (machine readable but not debugged)
• have the routine to retrieve data strings from program memory written (machine readable but not debugged)