Touch Panel Library
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Touch Panel Library

The mikroC PRO for PIC32 provides a library for working with Touch Panel.

Library Dependency Tree

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 atomic sbit DriveA; DriveA line. sbit DriveA at LATC13_bit;
extern sfr atomic sbit DriveB; DriveB line. sbit DriveB at LATC14_bit;
extern sfr atomic sbit DriveA_Direction; Direction of the DriveA pin. sbit DriveA_Direction at TRISC13_bit;
extern sfr atomic sbit DriveB_Direction; Direction of the DriveB pin. sbit DriveB_Direction at TRISC14_bit;

Library Routines

TP_Init

Prototype

void TP_Init(unsigned int display_width, unsigned int display_height, unsigned int readX_ChNo, unsigned int 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 
ADC1_Init();               // Initalize ADC module
TP_Init(128, 64, 6, 7);    // Initialize touch panel, dimensions 128x64
Notes

None.

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
Notes

None.

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 LATC13_bit;
sbit DriveB at LATC14_bit;
sbit DriveA_Direction at TRISC13_bit;
sbit DriveB_Direction at TRISC14_bit;
// End Touch Panel module connections

if (TP_Press_Detect()) {
  ...
}
Notes

None.

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) {
 ...
}
Notes

None.

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
Notes

None.

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
Notes

None.

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
Notes

None.

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
Notes

None.

Library Example

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

Copy Code To ClipboardCopy Code To Clipboard 
// Glcd module connections
sbit GLCD_D7 at RD3_bit;
sbit GLCD_D6 at RD2_bit;
sbit GLCD_D5 at RD1_bit;
sbit GLCD_D4 at RD0_bit;
sbit GLCD_D3 at RB3_bit;
sbit GLCD_D2 at RB2_bit;
sbit GLCD_D1 at RB1_bit;
sbit GLCD_D0 at RB0_bit;
sbit GLCD_D7_Direction at TRISD3_bit;
sbit GLCD_D6_Direction at TRISD2_bit;
sbit GLCD_D5_Direction at TRISD1_bit;
sbit GLCD_D4_Direction at TRISD0_bit;
sbit GLCD_D3_Direction at TRISB3_bit;
sbit GLCD_D2_Direction at TRISB2_bit;
sbit GLCD_D1_Direction at TRISB1_bit;
sbit GLCD_D0_Direction at TRISB0_bit;

sbit GLCD_CS1 at LATB4_bit;
sbit GLCD_CS2 at LATB5_bit;
sbit GLCD_RS  at LATF0_bit;
sbit GLCD_RW  at LATF1_bit;
sbit GLCD_EN  at LATF4_bit;
sbit GLCD_RST at LATF5_bit;
sbit GLCD_CS1_Direction at TRISB4_bit;
sbit GLCD_CS2_Direction at TRISB5_bit;
sbit GLCD_RS_Direction  at TRISF0_bit;
sbit GLCD_RW_Direction  at TRISF1_bit;
sbit GLCD_EN_Direction  at TRISF4_bit;
sbit GLCD_RST_Direction at TRISF5_bit;
// End Glcd module connections

// Touch Panel module connections
sbit DriveA at LATC13_bit;
sbit DriveB at LATC14_bit;
sbit DriveA_Direction at TRISC13_bit;
sbit DriveB_Direction at TRISC14_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() {
  ADPCFG = 0xFF3F;                                         // set AN6 and AN7 channel pins as analog

  DriveA_Direction = 0;                                    // Set DriveA pin as output
  DriveB_Direction = 0;                                    // Set DriveB pin as output

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

  ADC1_Init();                                             // Initalize ADC module
  TP_Init(128, 64, 6, 7);                                  // Initialize touch panel
  TP_Set_ADC_Threshold(3900);                              // 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",12,3,1);
  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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