NerdNos-Firmware/lib/TFT_eSPI/Extensions/Touch.cpp

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// The following touch screen support code by maxpautsch was merged 1/10/17
// https://github.com/maxpautsch
// Define TOUCH_CS is the user setup file to enable this code
// A demo is provided in examples Generic folder
// Additions by Bodmer to double sample, use Z value to improve detection reliability
// and to correct rotation handling
// See license in root directory.
/***************************************************************************************
** Function name: begin_touch_read_write - was spi_begin_touch
** Description: Start transaction and select touch controller
***************************************************************************************/
// The touch controller has a low SPI clock rate
inline void TFT_eSPI::begin_touch_read_write(void){
DMA_BUSY_CHECK;
CS_H; // Just in case it has been left low
#if defined (SPI_HAS_TRANSACTION) && defined (SUPPORT_TRANSACTIONS)
if (locked) {locked = false; spi.beginTransaction(SPISettings(SPI_TOUCH_FREQUENCY, MSBFIRST, SPI_MODE0));}
#else
spi.setFrequency(SPI_TOUCH_FREQUENCY);
#endif
SET_BUS_READ_MODE;
T_CS_L;
}
/***************************************************************************************
** Function name: end_touch_read_write - was spi_end_touch
** Description: End transaction and deselect touch controller
***************************************************************************************/
inline void TFT_eSPI::end_touch_read_write(void){
T_CS_H;
#if defined (SPI_HAS_TRANSACTION) && defined (SUPPORT_TRANSACTIONS)
if(!inTransaction) {if (!locked) {locked = true; spi.endTransaction();}}
#else
spi.setFrequency(SPI_FREQUENCY);
#endif
//SET_BUS_WRITE_MODE;
}
/***************************************************************************************
** Function name: Legacy - deprecated
** Description: Start/end transaction
***************************************************************************************/
void TFT_eSPI::spi_begin_touch() {begin_touch_read_write();}
void TFT_eSPI::spi_end_touch() { end_touch_read_write();}
/***************************************************************************************
** Function name: getTouchRaw
** Description: read raw touch position. Always returns true.
***************************************************************************************/
uint8_t TFT_eSPI::getTouchRaw(uint16_t *x, uint16_t *y){
uint16_t tmp;
begin_touch_read_write();
// Start YP sample request for x position, read 4 times and keep last sample
spi.transfer(0xd0); // Start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0xd0); // Read last 8 bits and start new YP conversion
tmp = spi.transfer(0); // Read first 8 bits
tmp = tmp <<5;
tmp |= 0x1f & (spi.transfer(0x90)>>3); // Read last 8 bits and start new XP conversion
*x = tmp;
// Start XP sample request for y position, read 4 times and keep last sample
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
spi.transfer(0); // Read first 8 bits
spi.transfer(0x90); // Read last 8 bits and start new XP conversion
tmp = spi.transfer(0); // Read first 8 bits
tmp = tmp <<5;
tmp |= 0x1f & (spi.transfer(0)>>3); // Read last 8 bits
*y = tmp;
end_touch_read_write();
return true;
}
/***************************************************************************************
** Function name: getTouchRawZ
** Description: read raw pressure on touchpad and return Z value.
***************************************************************************************/
uint16_t TFT_eSPI::getTouchRawZ(void){
begin_touch_read_write();
// Z sample request
int16_t tz = 0xFFF;
spi.transfer(0xb0); // Start new Z1 conversion
tz += spi.transfer16(0xc0) >> 3; // Read Z1 and start Z2 conversion
tz -= spi.transfer16(0x00) >> 3; // Read Z2
end_touch_read_write();
if (tz == 4095) tz = 0;
return (uint16_t)tz;
}
/***************************************************************************************
** Function name: validTouch
** Description: read validated position. Return false if not pressed.
***************************************************************************************/
#define _RAWERR 20 // Deadband error allowed in successive position samples
uint8_t TFT_eSPI::validTouch(uint16_t *x, uint16_t *y, uint16_t threshold){
uint16_t x_tmp, y_tmp, x_tmp2, y_tmp2;
// Wait until pressure stops increasing to debounce pressure
uint16_t z1 = 1;
uint16_t z2 = 0;
while (z1 > z2)
{
z2 = z1;
z1 = getTouchRawZ();
delay(1);
}
// Serial.print("Z = ");Serial.println(z1);
if (z1 <= threshold) return false;
getTouchRaw(&x_tmp,&y_tmp);
// Serial.print("Sample 1 x,y = "); Serial.print(x_tmp);Serial.print(",");Serial.print(y_tmp);
// Serial.print(", Z = ");Serial.println(z1);
delay(1); // Small delay to the next sample
if (getTouchRawZ() <= threshold) return false;
delay(2); // Small delay to the next sample
getTouchRaw(&x_tmp2,&y_tmp2);
// Serial.print("Sample 2 x,y = "); Serial.print(x_tmp2);Serial.print(",");Serial.println(y_tmp2);
// Serial.print("Sample difference = ");Serial.print(abs(x_tmp - x_tmp2));Serial.print(",");Serial.println(abs(y_tmp - y_tmp2));
if (abs(x_tmp - x_tmp2) > _RAWERR) return false;
if (abs(y_tmp - y_tmp2) > _RAWERR) return false;
*x = x_tmp;
*y = y_tmp;
return true;
}
/***************************************************************************************
** Function name: getTouch
** Description: read callibrated position. Return false if not pressed.
***************************************************************************************/
#define Z_THRESHOLD 350 // Touch pressure threshold for validating touches
uint8_t TFT_eSPI::getTouch(uint16_t *x, uint16_t *y, uint16_t threshold){
uint16_t x_tmp, y_tmp;
if (threshold<20) threshold = 20;
if (_pressTime > millis()) threshold=20;
uint8_t n = 5;
uint8_t valid = 0;
while (n--)
{
if (validTouch(&x_tmp, &y_tmp, threshold)) valid++;;
}
if (valid<1) { _pressTime = 0; return false; }
_pressTime = millis() + 50;
convertRawXY(&x_tmp, &y_tmp);
if (x_tmp >= _width || y_tmp >= _height) return false;
_pressX = x_tmp;
_pressY = y_tmp;
*x = _pressX;
*y = _pressY;
return valid;
}
/***************************************************************************************
** Function name: convertRawXY
** Description: convert raw touch x,y values to screen coordinates
***************************************************************************************/
void TFT_eSPI::convertRawXY(uint16_t *x, uint16_t *y)
{
uint16_t x_tmp = *x, y_tmp = *y, xx, yy;
if(!touchCalibration_rotate){
xx=(x_tmp-touchCalibration_x0)*_width/touchCalibration_x1;
yy=(y_tmp-touchCalibration_y0)*_height/touchCalibration_y1;
if(touchCalibration_invert_x)
xx = _width - xx;
if(touchCalibration_invert_y)
yy = _height - yy;
} else {
xx=(y_tmp-touchCalibration_x0)*_width/touchCalibration_x1;
yy=(x_tmp-touchCalibration_y0)*_height/touchCalibration_y1;
if(touchCalibration_invert_x)
xx = _width - xx;
if(touchCalibration_invert_y)
yy = _height - yy;
}
*x = xx;
*y = yy;
}
/***************************************************************************************
** Function name: calibrateTouch
** Description: generates calibration parameters for touchscreen.
***************************************************************************************/
void TFT_eSPI::calibrateTouch(uint16_t *parameters, uint32_t color_fg, uint32_t color_bg, uint8_t size){
int16_t values[] = {0,0,0,0,0,0,0,0};
uint16_t x_tmp, y_tmp;
for(uint8_t i = 0; i<4; i++){
fillRect(0, 0, size+1, size+1, color_bg);
fillRect(0, _height-size-1, size+1, size+1, color_bg);
fillRect(_width-size-1, 0, size+1, size+1, color_bg);
fillRect(_width-size-1, _height-size-1, size+1, size+1, color_bg);
if (i == 5) break; // used to clear the arrows
switch (i) {
case 0: // up left
drawLine(0, 0, 0, size, color_fg);
drawLine(0, 0, size, 0, color_fg);
drawLine(0, 0, size , size, color_fg);
break;
case 1: // bot left
drawLine(0, _height-size-1, 0, _height-1, color_fg);
drawLine(0, _height-1, size, _height-1, color_fg);
drawLine(size, _height-size-1, 0, _height-1 , color_fg);
break;
case 2: // up right
drawLine(_width-size-1, 0, _width-1, 0, color_fg);
drawLine(_width-size-1, size, _width-1, 0, color_fg);
drawLine(_width-1, size, _width-1, 0, color_fg);
break;
case 3: // bot right
drawLine(_width-size-1, _height-size-1, _width-1, _height-1, color_fg);
drawLine(_width-1, _height-1-size, _width-1, _height-1, color_fg);
drawLine(_width-1-size, _height-1, _width-1, _height-1, color_fg);
break;
}
// user has to get the chance to release
if(i>0) delay(1000);
for(uint8_t j= 0; j<8; j++){
// Use a lower detect threshold as corners tend to be less sensitive
while(!validTouch(&x_tmp, &y_tmp, Z_THRESHOLD/2));
values[i*2 ] += x_tmp;
values[i*2+1] += y_tmp;
}
values[i*2 ] /= 8;
values[i*2+1] /= 8;
}
// from case 0 to case 1, the y value changed.
// If the measured delta of the touch x axis is bigger than the delta of the y axis, the touch and TFT axes are switched.
touchCalibration_rotate = false;
if(abs(values[0]-values[2]) > abs(values[1]-values[3])){
touchCalibration_rotate = true;
touchCalibration_x0 = (values[1] + values[3])/2; // calc min x
touchCalibration_x1 = (values[5] + values[7])/2; // calc max x
touchCalibration_y0 = (values[0] + values[4])/2; // calc min y
touchCalibration_y1 = (values[2] + values[6])/2; // calc max y
} else {
touchCalibration_x0 = (values[0] + values[2])/2; // calc min x
touchCalibration_x1 = (values[4] + values[6])/2; // calc max x
touchCalibration_y0 = (values[1] + values[5])/2; // calc min y
touchCalibration_y1 = (values[3] + values[7])/2; // calc max y
}
// in addition, the touch screen axis could be in the opposite direction of the TFT axis
touchCalibration_invert_x = false;
if(touchCalibration_x0 > touchCalibration_x1){
values[0]=touchCalibration_x0;
touchCalibration_x0 = touchCalibration_x1;
touchCalibration_x1 = values[0];
touchCalibration_invert_x = true;
}
touchCalibration_invert_y = false;
if(touchCalibration_y0 > touchCalibration_y1){
values[0]=touchCalibration_y0;
touchCalibration_y0 = touchCalibration_y1;
touchCalibration_y1 = values[0];
touchCalibration_invert_y = true;
}
// pre calculate
touchCalibration_x1 -= touchCalibration_x0;
touchCalibration_y1 -= touchCalibration_y0;
if(touchCalibration_x0 == 0) touchCalibration_x0 = 1;
if(touchCalibration_x1 == 0) touchCalibration_x1 = 1;
if(touchCalibration_y0 == 0) touchCalibration_y0 = 1;
if(touchCalibration_y1 == 0) touchCalibration_y1 = 1;
// export parameters, if pointer valid
if(parameters != NULL){
parameters[0] = touchCalibration_x0;
parameters[1] = touchCalibration_x1;
parameters[2] = touchCalibration_y0;
parameters[3] = touchCalibration_y1;
parameters[4] = touchCalibration_rotate | (touchCalibration_invert_x <<1) | (touchCalibration_invert_y <<2);
}
}
/***************************************************************************************
** Function name: setTouch
** Description: imports calibration parameters for touchscreen.
***************************************************************************************/
void TFT_eSPI::setTouch(uint16_t *parameters){
touchCalibration_x0 = parameters[0];
touchCalibration_x1 = parameters[1];
touchCalibration_y0 = parameters[2];
touchCalibration_y1 = parameters[3];
if(touchCalibration_x0 == 0) touchCalibration_x0 = 1;
if(touchCalibration_x1 == 0) touchCalibration_x1 = 1;
if(touchCalibration_y0 == 0) touchCalibration_y0 = 1;
if(touchCalibration_y1 == 0) touchCalibration_y1 = 1;
touchCalibration_rotate = parameters[4] & 0x01;
touchCalibration_invert_x = parameters[4] & 0x02;
touchCalibration_invert_y = parameters[4] & 0x04;
}