Digilent Digital Discovery is a combined logic analyzer and pattern generator instrument and allows you to debug, visualize,
and simulate signals in digital systems. LCD displays are used in a wide range of devices. The most common version uses a 2×16 character array.
You can use Digital Discovery to understand the operations of the LCD display. To do so, you need the following hardware and software.
Then, you can plug the HD44780 LCD on LCD Keypad shield and stack the module on the Arduino Uno. You also need to download the sketch to the Arduino board. After that, you need to connect the Digital Discovery to the HD44780 LCD. The below picture shows the hardware set-up.
After you open WaveForms software and turn on Logic Analyzer instrument, you can add the following signals and buses
You can try different command and look at each bus and signal. When commands of 0x01 (“clear display”) and data 0x50 (letter “P” encoded in ASCII) are sent, you can see the LSB and 3rd bit are driven respectively.
Go through the step by step guideline and get the example code in the Digilent Wiki