Frank Vannieuwkerke
LPC1768 Mini-DK board with 2.8" SPI TFT and SPI touch
Dependencies: Mini-DK mbed SDFileSystem
WARNING: filetoflash (SD to CPU flash)
The SPI_TFT library called from Mini-DK.lib contains an option to copy an image from the SD card to the CPU flash memory. This allows you to use an image as background without speed loss when writing other text and graphics.
By default, this option is enabled.
It can be disabled by uncommenting the #define mentioned below in Mini_DK.h:
#define NO_FLASH_BUFFER
Since the flash memory has limited write endurance, DO NOT use this feature when you intend to read multiple images from the SD card (eg: when used as a photo frame).
Diff: Mini-DK/TouchADS7843/Touch.cpp
- Revision:
- 2:d0acbd263ec7
- Child:
- 3:fb4d62b5ffb3
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Mini-DK/TouchADS7843/Touch.cpp Thu Jan 03 10:54:09 2013 +0000
@@ -0,0 +1,261 @@
+// Code based on Carlos E. Vidales tutorial : How To Calibrate Touch Screens
+// http://www.embedded.com/design/configurable-systems/4023968/How-To-Calibrate-Touch-Screens
+
+#include "Touch.h"
+#include "mbed.h"
+#include "Arial12x12.h"
+
+/*Coordinate ScreenSample[3] = {
+ { 45, 45 },
+ { 45, 270},
+ { 190,190}
+} ;*/
+/*Coordinate DisplaySample[3] = {
+ { 45, 45 },
+ { 45, 270},
+ { 190,190}
+} ;*/
+
+#define THRESHOLD 2
+
+TouchScreenADS7843::TouchScreenADS7843(PinName tp_mosi, PinName tp_miso, PinName tp_sclk, PinName tp_cs, PinName tp_irq)
+ : _tp_spi(tp_mosi, tp_miso, tp_sclk), _tp_cs(tp_cs), _tp_irq(tp_irq)
+ {
+ DisplaySample[0].x=45;
+ DisplaySample[0].y=45;
+ DisplaySample[1].x=45;
+ DisplaySample[1].y=270;
+ DisplaySample[2].x=190;
+ DisplaySample[2].y=190;
+ ScreenSample[0].x=45;
+ ScreenSample[0].y=45;
+ ScreenSample[1].x=45;
+ ScreenSample[1].y=270;
+ ScreenSample[2].x=190;
+ ScreenSample[2].y=190;
+ _tp_cs=1;
+ _tp_spi.frequency(500000);
+ _tp_spi.format(8,0); // 8 bit spi mode 0
+ }
+
+int TouchScreenADS7843::Read_XY(unsigned char XY)
+{
+ unsigned char msb, lsb;
+ unsigned int Temp;
+
+ Temp=0;
+ _tp_cs=0;
+ wait_us(SPI_RD_DELAY);
+ _tp_spi.write(XY);
+ wait_us(SPI_RD_DELAY);
+ msb = _tp_spi.write(0x00); // msb
+ wait_us(SPI_RD_DELAY);
+ lsb = _tp_spi.write(0x00); // lsb
+ _tp_cs=1;
+ Temp = ((msb << 8 ) | lsb);
+ Temp >>= 3;
+ Temp &= 0xfff;
+ Temp /= 4; // Scaling : return value range must be between 0 and 1024
+// Temp = (((msb & 0x7f) <<8) | lsb) >> 3; // 12 bit
+ return(Temp);
+}
+
+
+void TouchScreenADS7843::TP_GetAdXY(int *x,int *y)
+{
+ int adx,ady;
+ adx = Read_XY(CHX);
+ wait_us(1);
+ ady = Read_XY(CHY);
+ *x = adx;
+ *y = ady;
+}
+
+void TouchScreenADS7843::TP_DrawPoint(unsigned int Xpos,unsigned int Ypos, unsigned int color)
+{
+/* LCD->wr_reg(0x03, 0x1030);
+ LCD->WindowMax();
+ LCD->pixel(Xpos,Ypos,color);
+ LCD->pixel(Xpos+1,Ypos,color);
+ LCD->pixel(Xpos,Ypos+1,color);
+ LCD->pixel(Xpos+1,Ypos+1,color);*/
+}
+
+void TouchScreenADS7843::DrawCross(unsigned int Xpos,unsigned int Ypos)
+{
+/* LCD->line(Xpos-15,Ypos,Xpos-2,Ypos,White);
+ LCD->line(Xpos+2,Ypos,Xpos+15,Ypos,White);
+ LCD->line(Xpos,Ypos-15,Xpos,Ypos-2,White);
+ LCD->line(Xpos,Ypos+2,Xpos,Ypos+15,White);
+
+ LCD->line(Xpos-15,Ypos+15,Xpos-7,Ypos+15,DarkGrey);
+ LCD->line(Xpos-15,Ypos+7,Xpos-15,Ypos+15,DarkGrey);
+
+ LCD->line(Xpos-15,Ypos-15,Xpos-7,Ypos-15,DarkGrey);
+ LCD->line(Xpos-15,Ypos-7,Xpos-15,Ypos-15,DarkGrey);
+
+ LCD->line(Xpos+7,Ypos+15,Xpos+15,Ypos+15,DarkGrey);
+ LCD->line(Xpos+15,Ypos+7,Xpos+15,Ypos+15,DarkGrey);
+
+ LCD->line(Xpos+7,Ypos-15,Xpos+15,Ypos-15,DarkGrey);
+ LCD->line(Xpos+15,Ypos-15,Xpos+15,Ypos-7,DarkGrey);*/
+}
+
+unsigned char TouchScreenADS7843::Read_Ads7846(Coordinate * screenPtr)
+{
+ int m0,m1,m2,TP_X[1],TP_Y[1],temp[3];
+ uint8_t count=0;
+ int buffer[2][9]={{0},{0}};
+ do
+ {
+ TP_GetAdXY(TP_X,TP_Y);
+ buffer[0][count]=TP_X[0];
+ buffer[1][count]=TP_Y[0];
+ count++;
+ }
+ while(!_tp_irq && (count < 9));
+ if(count==9)
+ {
+ temp[0]=(buffer[0][0]+buffer[0][1]+buffer[0][2])/3;
+ temp[1]=(buffer[0][3]+buffer[0][4]+buffer[0][5])/3;
+ temp[2]=(buffer[0][6]+buffer[0][7]+buffer[0][8])/3;
+ m0=temp[0]-temp[1];
+ m1=temp[1]-temp[2];
+ m2=temp[2]-temp[0];
+ m0=m0>0?m0:(-m0);
+ m1=m1>0?m1:(-m1);
+ m2=m2>0?m2:(-m2);
+ if( (m0>THRESHOLD) && (m1>THRESHOLD) && (m2>THRESHOLD) ) return 0;
+ if(m0<m1)
+ {
+ if(m2<m0)
+ screenPtr->x=(temp[0]+temp[2])/2;
+ else
+ screenPtr->x=(temp[0]+temp[1])/2;
+ }
+ else if(m2<m1)
+ screenPtr->x=(temp[0]+temp[2])/2;
+ else
+ screenPtr->x=(temp[1]+temp[2])/2;
+
+ temp[0]=(buffer[1][0]+buffer[1][1]+buffer[1][2])/3;
+ temp[1]=(buffer[1][3]+buffer[1][4]+buffer[1][5])/3;
+ temp[2]=(buffer[1][6]+buffer[1][7]+buffer[1][8])/3;
+ m0=temp[0]-temp[1];
+ m1=temp[1]-temp[2];
+ m2=temp[2]-temp[0];
+ m0=m0>0?m0:(-m0);
+ m1=m1>0?m1:(-m1);
+ m2=m2>0?m2:(-m2);
+ if( (m0>THRESHOLD) && (m1>THRESHOLD) && (m2>THRESHOLD) ) return 0;
+
+ if(m0<m1)
+ {
+ if(m2<m0)
+ screenPtr->y=(temp[0]+temp[2])/2;
+ else
+ screenPtr->y=(temp[0]+temp[1])/2;
+ }
+ else if(m2<m1)
+ screenPtr->y=(temp[0]+temp[2])/2;
+ else
+ screenPtr->y=(temp[1]+temp[2])/2;
+ return 1;
+ }
+ return 0;
+}
+
+uint8_t TouchScreenADS7843::setCalibrationMatrix( Coordinate * displayPtr,
+ Coordinate * screenPtr,
+ Matrix * matrixPtr)
+{
+ uint8_t retTHRESHOLD = 0 ;
+ // K = (Xs0 - Xs2)*(Ys1 - Ys2) - (Xs1 - Xs2)*(Ys0 - Ys2)
+ matrixPtr->Divider = ((screenPtr[0].x - screenPtr[2].x) * (screenPtr[1].y - screenPtr[2].y)) -
+ ((screenPtr[1].x - screenPtr[2].x) * (screenPtr[0].y - screenPtr[2].y)) ;
+ if( matrixPtr->Divider == 0 )
+ {
+ retTHRESHOLD = 1;
+ }
+ else
+ {
+ // (Xd0 - Xd2)*(Ys1 - Ys2) - (Xd1 - Xd2)*(Ys0 - Ys2)
+ // A = ---------------------------------------------------
+ // K
+ matrixPtr->An = ((displayPtr[0].x - displayPtr[2].x) * (screenPtr[1].y - screenPtr[2].y)) -
+ ((displayPtr[1].x - displayPtr[2].x) * (screenPtr[0].y - screenPtr[2].y)) ;
+ // (Xs0 - Xs2)*(Xd1 - Xd2) - (Xd0 - Xd2)*(Xs1 - Xs2)
+ // B = ---------------------------------------------------
+ // K
+ matrixPtr->Bn = ((screenPtr[0].x - screenPtr[2].x) * (displayPtr[1].x - displayPtr[2].x)) -
+ ((displayPtr[0].x - displayPtr[2].x) * (screenPtr[1].x - screenPtr[2].x)) ;
+ // Ys0*(Xs2*Xd1 - Xs1*Xd2) + Ys1*(Xs0*Xd2 - Xs2*Xd0) + Ys2*(Xs1*Xd0 - Xs0*Xd1)
+ // C = ----------------------------------------------------------------------------
+ // K
+ matrixPtr->Cn = (screenPtr[2].x * displayPtr[1].x - screenPtr[1].x * displayPtr[2].x) * screenPtr[0].y +
+ (screenPtr[0].x * displayPtr[2].x - screenPtr[2].x * displayPtr[0].x) * screenPtr[1].y +
+ (screenPtr[1].x * displayPtr[0].x - screenPtr[0].x * displayPtr[1].x) * screenPtr[2].y ;
+ // (Yd0 - Yd2)*(Ys1 - Ys2) - (Yd1 - Yd2)*(Ys0 - Ys2)
+ // D = ---------------------------------------------------
+ // K
+ matrixPtr->Dn = ((displayPtr[0].y - displayPtr[2].y) * (screenPtr[1].y - screenPtr[2].y)) -
+ ((displayPtr[1].y - displayPtr[2].y) * (screenPtr[0].y - screenPtr[2].y)) ;
+ // (Xs0 - Xs2)*(Yd1 - Yd2) - (Yd0 - Yd2)*(Xs1 - Xs2)
+ // E = ---------------------------------------------------
+ // K
+ matrixPtr->En = ((screenPtr[0].x - screenPtr[2].x) * (displayPtr[1].y - displayPtr[2].y)) -
+ ((displayPtr[0].y - displayPtr[2].y) * (screenPtr[1].x - screenPtr[2].x)) ;
+ // Ys0*(Xs2*Yd1 - Xs1*Yd2) + Ys1*(Xs0*Yd2 - Xs2*Yd0) + Ys2*(Xs1*Yd0 - Xs0*Yd1)
+ // F = ----------------------------------------------------------------------------
+ // K
+ matrixPtr->Fn = (screenPtr[2].x * displayPtr[1].y - screenPtr[1].x * displayPtr[2].y) * screenPtr[0].y +
+ (screenPtr[0].x * displayPtr[2].y - screenPtr[2].x * displayPtr[0].y) * screenPtr[1].y +
+ (screenPtr[1].x * displayPtr[0].y - screenPtr[0].x * displayPtr[1].y) * screenPtr[2].y ;
+ }
+ return( retTHRESHOLD ) ;
+}
+
+uint8_t TouchScreenADS7843::getDisplayPoint(void)
+{
+ uint8_t retTHRESHOLD = 0 ;
+
+ if( matrix.Divider != 0 )
+ {
+ // XD = AX+BY+C
+ display.x = ( (matrix.An * screen.x) +
+ (matrix.Bn * screen.y) +
+ matrix.Cn
+ ) / matrix.Divider ;
+ // YD = DX+EY+F
+ display.y = ( (matrix.Dn * screen.x) +
+ (matrix.En * screen.y) +
+ matrix.Fn
+ ) / matrix.Divider ;
+ }
+ else
+ {
+ retTHRESHOLD = 1;
+ }
+ return(retTHRESHOLD);
+}
+
+void TouchScreenADS7843::TouchPanel_Calibrate(void)
+{
+ uint8_t i;
+ Coordinate screen_cal;
+ setCalibrationMatrix( &DisplaySample[0],&ScreenSample[0],&matrix) ;
+// LCD->set_font((unsigned char*) Arial12x12);
+ for(i=0;i<3;i++)
+ {
+// LCD->cls();
+// LCD->locate(10,10);
+// LCD->printf("Touch crosshair to calibrate");
+ wait_ms(500);
+ DrawCross(DisplaySample[i].x,DisplaySample[i].y);
+ do {} while (!Read_Ads7846(&screen_cal));
+ ScreenSample[i].x= screen_cal.x;ScreenSample[i].y= screen_cal.y;
+ }
+ setCalibrationMatrix( &DisplaySample[0],&ScreenSample[0],&matrix) ;
+// LCD->cls();
+}
+
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Repository details
| Type: | Program |
|---|---|
| Mbed OS support: | Mbed 2 deprecated |
| Created: | 11 Dec 2012 |
| Imports: | 398 |
| Forks: | 2 |
| Commits: | 18 |
| Dependents: | 0 |
| Dependencies: | 3 |
| Followers: | 13 |
| Issues: | 0 |
The code in this repository is MIT licensed.