Touch Panel Library

The mikroC PRO for PIC provides a library for working with Touch Panel.

Library Dependency Tree

External dependencies of Touch Panel Library

The following variables must be defined in all projects using Touch Panel Library:	Description :	Example :
`extern sfr sbit DriveA;`	DriveA line.	`sbit DriveA at RC0_bit;`
`extern sfr sbit DriveB;`	DriveB line.	`sbit DriveB at RC1_bit;`
`extern sfr sbit DriveA_Direction;`	Direction of the DriveA pin.	`sbit DriveA_Direction at TRISC0_bit;`
`extern sfr sbit DriveB_Direction;`	Direction of the DriveB pin.	`sbit DriveB_Direction at TRISC1_bit;`

TP_Init

Prototype	void TP_Init(unsigned int display_width, unsigned int display_height, char readX_ChNo, char readY_ChNo);
Description	Initialize touch panel display. Default touch panel ADC threshold value is set to 3900.
Parameters	`display_width:` set display width. `display_height:` set display height. `readX_ChNo:` read X coordinate from desired ADC channel. `readY_ChNo:` read Y coordinate from desired ADC channel.
Returns	Nothing.
Requires	Before calling this function initialize ADC module.
Example	ADC_Init(); // Initalize ADC module TP_Init(128, 64, 6, 7); // Initialize touch panel, dimensions 128x64

TP_Set_ADC_Threshold

Prototype	void TP_Set_ADC_Threshold(unsigned int threshold);
Description	Set custom ADC threshold value, call this function after `TP_Init`.
Parameters	`threshold:` custom ADC threshold value.
Returns	Nothing.
Requires	`TP_Init` has to be called before using this routine.
Example	TP_Set_ADC_Threshold(3900); // Set touch panel ADC threshold

TP_Press_Detect

Prototype	char TP_Press_Detect();
Description	Detects if the touch panel has been pressed.
Parameters	None.
Returns	`1` - if touch panel is pressed. `0` - otherwise.
Requires	Global variables : `DriveA:` DriveA. `DriveB:` DriveB. `DriveA_Direction:` Direction of DriveA pin. `DriveB_Direction:` Direction of DriveB pin. must be defined before using this function.
Example	// Touch Panel module connections sbit DriveA at RC0_bit; sbit DriveB at RC1_bit; sbit DriveA_Direction at TRISC0_bit; sbit DriveB_Direction at TRISC1_bit; // End Touch Panel module connections if (TP_Press_Detect()) { ... }

TP_Get_Coordinates

Prototype	char TP_Get_Coordinates(unsigned int x_coordinate, unsigned int* *y_coordinate);
Description	Get touch panel coordinates and store them in `x_coordinate` and `y_coordinate` parameters.
Parameters	`x_coordinate:` x coordinate of the place of touch. `y_coordinate:` y coordinate of the place of touch.
Returns	`0` - if reading is within display dimension range. `1` - if reading is out of display dimension range.
Requires	Nothing.
Example	if (TP_Get_Coordinates(&x_coord, &y_coord) == 0) { ... }

TP_Calibrate_Bottom_Left

Prototype	void TP_Calibrate_Bottom_Left();
Description	Calibrate bottom left corner of the touch Panel.
Parameters	None.
Returns	Nothing.
Requires	Nothing.
Example	TP_Calibrate_Bottom_Left(); // Calibration of bottom left corner

TP_Calibrate_Upper_Right

Prototype	void TP_Calibrate_Upper_Right();
Description	Calibrate upper right corner of the touch panel.
Parameters	None.
Returns	Nothing.
Requires	Nothing.
Example	TP_Calibrate_Upper_Right(); // Calibration of upper right corner

TP_Get_Calibration_Consts

Prototype	void TP_Get_Calibration_Consts(unsigned int x_min, unsigned int* x_max, unsigned int* y_min, unsigned int* *y_max);
Description	Gets calibration constants after calibration is done and stores them in `x_min`, `x_max`, `y_min` and `y_max` parameters.
Parameters	`x_min:` x coordinate of the bottom left corner of the working area. `x_max:` x coordinate of the upper right corner of the working area. `y_min:` y coordinate of the bottom left corner of the working area. `y_max:` y coordinate of the upper right corner of the working area.
Returns	Nothing.
Requires	Nothing.
Example	TP_Get_Calibration_Consts(&x_min, &y_min, &x_max, &y_max); // Get calibration constants

TP_Set_Calibration_Consts

Prototype	void TP_Set_Calibration_Consts(unsigned int x_min, unsigned int x_max, unsigned int y_min, unsigned int y_max);
Description	Sets calibration constants.
Parameters	`x_min:` x coordinate of the bottom left corner of the working area. `x_max:` x coordinate of the upper right corner of the working area. `y_min:` y coordinate of the bottom left corner of the working area. `y_max:` y coordinate of the upper right corner of the working area.
Returns	Nothing.
Requires	Nothing.
Example	TP_Set_Calibration_Consts(148, 3590, 519, 3370); // Set calibration constants

Library Example

The following drawing demo tests routines of the Touch Panel library :

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// Glcd module connections
char GLCD_DataPort at PORTD;

sbit GLCD_CS1 at RB0_bit;
sbit GLCD_CS2 at RB1_bit;
sbit GLCD_RS  at RB2_bit;
sbit GLCD_RW  at RB3_bit;
sbit GLCD_EN  at RB4_bit;
sbit GLCD_RST at RB5_bit;

sbit GLCD_CS1_Direction at TRISB0_bit;
sbit GLCD_CS2_Direction at TRISB1_bit;
sbit GLCD_RS_Direction  at TRISB2_bit;
sbit GLCD_RW_Direction  at TRISB3_bit;
sbit GLCD_EN_Direction  at TRISB4_bit;
sbit GLCD_RST_Direction at TRISB5_bit;
// End Glcd module connections

// Touch Panel module connections
sbit DriveA at RC0_bit;
sbit DriveB at RC1_bit;
sbit DriveA_Direction at TRISC0_bit;
sbit DriveB_Direction at TRISC1_bit;
// End Touch Panel module connections

bit          write_erase;
char         pen_size;
char write_msg[] = "WRITE";                                // GLCD menu messages
char clear_msg[] = "CLEAR";
char erase_msg[] = "ERASE";
unsigned int x_coord, y_coord;

void Initialize() {
  DriveA_Direction = 0;                                    // Set DriveA pin as output
  DriveB_Direction = 0;                                    // Set DriveB pin as output
  ANSEL  = 3;                                              // Configure AN0 and AN1 pins as analog inputs
  ANSELH = 0;                                              // and other AN pins as digital I/O
  TRISA  = 3;

  C1ON_bit = 0;                                            // Disable comparators
  C2ON_bit = 0;

  Glcd_Init();                                             // Initialize GLCD
  Glcd_Fill(0);                                            // Clear GLCD

  ADC_Init();                                              // Initialize ADC
  TP_Init(128, 64, 0, 1);                                  // Initialize touch panel
  TP_Set_ADC_Threshold(900);                               // Set touch panel ADC threshold
}

void Calibrate() {

  Glcd_Dot(0,63,1);                                        // Draw bottom left dot
  Glcd_Write_Text("TOUCH BOTTOM LEFT",12,3,1);
  TP_Calibrate_Bottom_Left();                              // Calibration of bottom left corner
  Delay_ms(1000);

  Glcd_Dot(0,63,0);                                        // Clear bottom left dot
  Glcd_Dot(127,0,1);                                       // Draw upper right dot
  Glcd_Write_Text("                 ",12,3,1);
  Glcd_Write_Text("TOUCH UPPER RIGHT",12,4,1);
  TP_Calibrate_Upper_Right();                              // Calibration of upper right corner

  Delay_ms(1000);
}

void main() {

  Initialize();

  Glcd_Write_Text("CALIBRATION",32,3,1);
  Delay_ms(1000);
  Glcd_Fill(0);                                            // Clear GLCD
  Calibrate();

  Glcd_Fill(0);
  Glcd_Write_Text("WRITE ON SCREEN", 20, 5, 1) ;
  Delay_ms(1000);

  Glcd_Fill(0);                                            // Clear GLCD
  Glcd_V_Line(0,7,0,1);
  Glcd_Write_Text(clear_msg,1,0,0);
  Glcd_V_Line(0,7,97,1);
  Glcd_Write_Text(erase_msg,98,0,0);

  // Pen Menu:
  Glcd_Rectangle(41,0,52,9,1);
  Glcd_Box(45,3,48,6,1);
  Glcd_Rectangle(63,0,70,7,1);
  Glcd_Box(66,3,67,4,1);
  Glcd_Rectangle(80,0,86,6,1);
  Glcd_Dot(83,3,1);

  write_erase = 1;
  pen_size = 1;
  while (1) {

    if (TP_Press_Detect()) {
      // After a PRESS is detected read X-Y and convert it to 128x64 space
      if (TP_Get_Coordinates(&x_coord, &y_coord) == 0) {

        if ((x_coord < 31) && (y_coord < 8)) {

          Glcd_Fill(0);

          // Pen Menu:
          Glcd_Rectangle(41,0,52,9,1);
          Glcd_Box(45,3,48,6,1);
          Glcd_Rectangle(63,0,70,7,1);
          Glcd_Box(66,3,67,4,1);
          Glcd_Rectangle(80,0,86,6,1);
          Glcd_Dot(83,3,1);

          Glcd_V_Line(0,7,0,1);
          Glcd_Write_Text(clear_msg,1,0,0);
          Glcd_V_Line(0,7,97,1);
          if (write_erase)
            Glcd_Write_Text(erase_msg,98,0,0);
          else
            Glcd_Write_Text(write_msg,98,0,0);
          }

        // If write/erase is pressed
        if ((x_coord > 96) && (y_coord < 8)) {
          if (write_erase) {
            write_erase = 0;
            Glcd_Write_Text(write_msg,98,0,0);
            Delay_ms(500);
            }
          else {
            write_erase = 1;
            Glcd_Write_Text(erase_msg,98,0,0);
            Delay_ms(500);
            }
          }

        // If pen size is selected
        if ((x_coord >= 41) && (x_coord <= 52) && (y_coord <= 9))
          pen_size = 3;

        if ((x_coord >= 63) && (x_coord <= 70) && (y_coord <= 7))
          pen_size = 2;

        if ((x_coord >= 80) && (x_coord <= 86) && (y_coord <= 6))
          pen_size = 1;

        if (y_coord < 11)
          continue;

        switch (pen_size) {
          case 1 : {
                     if ( (x_coord >= 0) && (y_coord >= 0) && (x_coord <= 127) && (y_coord <= 63) )
                       Glcd_Dot(x_coord, y_coord, write_erase);
                     break;
                   }
          case 2 : {
                     if ( (x_coord >= 0) && (y_coord >= 0) && (x_coord <= 127-1) && (y_coord <= 63-1) )
                       Glcd_Box(x_coord, y_coord, x_coord + 1, y_coord + 1, write_erase);
                     break;
                   }
          case 3 : {
                     if ( (x_coord >= 1) && (y_coord >= 1) && (x_coord <= 127-2) && (y_coord <= 63-2) )
                       Glcd_Box(x_coord-1, y_coord-1, x_coord + 2, y_coord + 2, write_erase);
                     break;
                   }
        }
      }
    }
  }
}

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