VHDL coding to Initialize Touchscreen, Display image and Detect Touch

ECE520 Homework 7: Touchscreen LCD Touch Detection

Reference: AD7843 Touch Screen Digitizer Datasheet

In Homework 6, VHDL codes are written to initialize the Terasic Display Panel to support:

1. 800 pixels by 480 pixels display resolution

2. Active low horizontal and vertical synchronization signals.

3. Normal image display.

4. Other options at your discretion

And to display three 64-bit x 64-bit clipart images, with appropriate resolution, on the display

according to the format specified above.

In this homework, you will write VHDL codes to detect the touch on the LCD screen and store the X

coordinate in xReg and Y coordinates in yReg. It shall be your choice of the coordinate resolution

and conversion scheme (single ended or ratiometric). Since this homework will not be tested on

AD7843, you will emulate AD7843 outputs in simulation. In other words, you set the inputs of

Homework 7, which are assumed to be connected to the outputs of AD7843 to match the actual

outputs of AD7843 (you make up the coordinate value). You include only these signals from AD7843

in your entity. Entity inputs: penirq_n, busy and dout; Entity outputs: cs_n, dclk and din. In addition,

you shall add two additional outputs in Entity to reflect the xReg and yReg values to the outputs for

debugging purposes. This way you can see if the coordinates you set up match the xReg and yReg

values in simulation.

. . . . . . . . . . . . . . . .

You make up these bit values

Material to submit:

1. Copy of a well documented VHDL codes.

2. Include the simulation printout that shows the detection of a touch on the LCD display.

Manually verify that the X and Y coordinates are correct and the timing requirement is satisfied.