www.micro-examples.com : TouchClock

Revision as of 12:51, 9 February 2012

Design your own GLCD Touch Clock

TouchClock : a PIC18 GLCD touchscreen clock

Let me introduce TouchClock to you with this short video clip :

The idea of this project is to use a graphic LCD with a touchscreen and a built-in sprite editor to design your own clock, and shows how to connect a resistive touchscreen directly to a PIC with no additional hardware.

This project also includes a ready-to use touchscreen library for PIC

Circuit Schematic

This is how to connect the 4-wire resistive touchscreen directly to the PIC :

How the library reads the X raw coordinate of a touch  :

• X+ and X- are in high Z : RA0 and RA2 are inputs
• Y+ is set to +5V : RA3 is output high
• Y- is set to 0V : RA1 is output low
• X+ voltage is read by ADC
• Y+ is set to 0V : RA3 is output low
• Y- is set to 5V: RA1 is output high
• X- voltage is read by ADC and averaged with X+ value, the result is the raw X coordinate.
• The same is then done to read the Y coordinate, please see TSlib.c file in .ZIP file above.

X and Y raw coordinates are then adjusted using calibration coordinates to get X and Y coordinates in pixel.

C Source code

Download project

Download LCDscope-project.ZIP file for mikroC : File:LCDscope-project.zip

Includes :

• mikroC PRO project files for PIC18F4620, should work also with most of PIC
• LCDscope C source code
• LCDscope .HEX files

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