cbarberis
Joined: 01 Oct 2003
Posts: 172
Location: Punta Gorda, Florida USA
|
| A Driver for the XPT2046 or TI TSC2046 Touch Controllers |
 Posted: Mon Aug 10, 2020 3:47 pm |
 |
|
This is a functional driver you can use on the XPT2046 or the TI TSC2046, it may also work with the ADS7843 but I cannot attest to that particular device.
My testing was done on a cheap ILI9341 (240 X 320) TFT display that has this touch screen the module is excellent and only costs $10 from Amazon. I did not include here the driver and libraries for the TFT display this is just for the touch controller and you can easily test it via the serial port.
| Code: |
///////////////////////////////////////////////////////////////////////////////////
// Interfacing dsPIC33FJ128GP802 microcontroller touch display using the XPT2046
// Touch Controller which is the same as TSC2046 from TI,This quick test does not
// include the ILI9341 TFT LCD display just a basic functionality test using the
// serial port to report X,Y and Z touch values
// Carlos Barberis
// August 10, 2020
//////////////////////////////////////////////////////////////////////////////////
#include <33FJ128GP802.h>
#device ADC=12
#device ICSP=1
//#device ICD=TRUE
#FUSES NOWDT //No Watch Dog Timer
//#FUSES WDT //be careful using WDT make sure is timed correctly otherwise it will never work
#FUSES WPRES32 //Watch Dog Timer PreScalar 1:32
#FUSES WPOSTS10 //Watch Dog Timer PostScalar 1:512
#FUSES CKSFSM //Clock Switching is enabled, fail Safe clock monitor is enabled
#FUSES NODEBUG
//#FUSES DEBUG
#use delay(internal = 64MHz)
//////////////////////// Connector Wiring for Touch Module //////////////////////////
// TOUCH-MISO --> PIN_B4
// TOUCH-IRQ --> PIN_B7
// TOUCH-SCK --> PIN_B6
// TOUCH-MOSI --> PIN_B5
// TOUCH-CS --> PIN_B8
///////////////////////////////////////////////////////////////////////////////
// define XPT2046 Touch module pin connections for this particular setup
#define TOUCH_CS PIN_B8 // chip select pin
#define TOUCH_IRQ PIN_B7 // Interrupt request
#pin_select SDI2=PIN_B4
#pin_select SDO2=PIN_B5
#pin_select SCK2OUT=PIN_B6
#pin_select U1TX=PIN_B14
#pin_select U1RX=PIN_B15
#use spi(MASTER, SPI2, MODE=0, BITS=8, baud=2000000,stream = TOUCH)
#use rs232(UART1, baud=9600,restart_wdt, errors,stream= USART1) // connected to USB serial
/// Function Prototypes ///////
void ext0_isr(void);
void ReadTouch_XYZData(void);
void ReadTouch_XData(void);
void ReadTouch_YData(void);
unsigned int X_Val,Y_Val;
unsigned int Z_Val,Z1,Z2;
unsigned int xraw,yraw;
unsigned int ScreenRotation = 1; //screen rotation
int1 TOUCH_FLAG = 0;
#define X_COMMAND_BYTE 0xD0 // get X values
#define Y_COMMAND_BYTE 0x90 // get Y values
#define Z1_COMMAND_BYTE 0xB1 // get Z1 value
#define Z2_COMMAND_BYTE 0xC1 // get Z2 value
#define MSB_BIT_MASK 0x7F // Bit mask for MSB byte
#define Z_THRESHOLD 400
#int_ext0
void ext0_isr() {
TOUCH_FLAG = 1;
}
void ReadTouch_XData() { // read 12 bit data from SPI bus after sending a command byte
unsigned int8 MSB =0,LSB =0;
output_low(PIN_B8);
delay_us(2);
SPI_XFER(TOUCH,X_COMMAND_BYTE); // send command byte twice to dump first reading
SPI_XFER(TOUCH,X_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);
output_high(PIN_B8);
xraw = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
}
void ReadTouch_YData() { // read 12 bit data from SPI bus after sending a command byte
unsigned int8 MSB =0,LSB =0;
output_low(PIN_B8);
delay_us(2);
SPI_XFER(TOUCH,Y_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);
output_high(PIN_B8);
yraw = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
}
void ReadTouch_XYZData() { // read 12 bit data from SPI bus after sending a command byte for X,Y,Z1&Z2 measurements
unsigned int8 MSB =0,LSB =0;
output_low(PIN_B8);
delay_us(2);
/////////////////////Gather Z pressure readings////////////////////////////////////
SPI_XFER(TOUCH,Z1_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);
Z1 = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
SPI_XFER(TOUCH,Z2_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);
Z2 = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
Z_Val = Z1 + 4095;
Z_Val -= Z2;
/////////////////////////////////////////////////////////
if(Z_Val >= Z_THRESHOLD) { // if we have more than the pressure threshold then read X&Y data
SPI_XFER(TOUCH,X_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);
xraw = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
SPI_XFER(TOUCH,Y_COMMAND_BYTE); // send command byte
MSB = SPI_XFER(TOUCH,0);
LSB = SPI_XFER(TOUCH,0);;
output_high(PIN_B8);
yraw = (((MSB & MSB_BIT_MASK) << 8)+ LSB) >> 3;
}
output_high(PIN_B8); // in case Z_Val did not qualify lets bring CS high
switch (ScreenRotation) { /// We need to know the display rotation to compensate for X,Y locations
case 1:
X_Val = 4095 - yraw;
Y_Val = 4095 - xraw;
break;
case 2:
X_Val = xraw;
Y_Val = yraw;
break;
case 3:
X_Val = yraw;
Y_Val = 4095 - xraw;
break;
default: // 4
X_Val = 4095 - xraw;
Y_Val = 4095 - yraw;
}
}
/////////////////////////////////// TEST PROGRAM /////////////////////////////////////////////////
void main() {
set_tris_b (0x9090);
set_pullup(true, PIN_B7);
enable_interrupts(INT_EXT0);
ext_int_edge( H_TO_L );
enable_interrupts(INTR_GLOBAL);
ReadTouch_XData(); // just to init once may not be really needed
while(1) {
if(TOUCH_FLAG)
{
while(!input(PIN_B7)) {
ReadTouch_XYZData();
delay_ms(100);
printf("XposRaw value = %lu , ",xraw);
printf("YposRaw value = %lu , ",yraw);
printf("Xpos value = %lu , ",X_Val);
printf("Ypos value = %lu , ",Y_Val);
printf("Z value = %lu \r\n",Z_Val);
}
TOUCH_FLAG = 0;}
delay_ms(100);
}
}
////////////////////////////////////////// END OF FILE ///////////////////////////////////////////////////
|
Enjoy!!! |
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
