tsTouchError_t tsRead(tsTouchData_t* data) {
uint32_t x1, y1;
// Assign pressure levels regardless of touch state
tsReadZ(&data->z1, &data->z2);
data->xraw = 0;
data->yraw = 0;
data->xlcd = 0;
data->ylcd = 0;
// Abort if the screen is not being touched (0 levels reported)
if (data->z1 < _tsThreshhold) {
data->valid = false;
return TS_ERROR_NONE;
}
nopDelay(CFG_TFTLCD_TS_DELAYBETWEENSAMPLES);
// Get two X/Y readings and compare results
x1 = tsReadX();
y1 = tsReadY();
// X/Y seems to be valid and reading has been confirmed twice
data->xraw = x1;
data->yraw = y1;
// Convert x/y values to pixel location with matrix multiply
tsPoint_t location, touch;
touch.x = x1;
touch.y = y1;
getDisplayPoint(&location, &touch, &_tsMatrix);
data->xlcd = location.x;
data->ylcd = location.y;
data->valid = true;
return TS_ERROR_NONE;
}
void tsCalibrate(void)
{
lcdOrientation_t orientation;
uint16_t right2, top2, left2, bottom2;
bool passed = false;
// Determine screen orientation before starting calibration
orientation = lcdGetOrientation();
/* -------------- Welcome Screen --------------- */
tsRenderCalibrationScreen(lcdGetWidth() / 2, lcdGetHeight() / 2, 5);
// Delay to avoid multiple touch events
systickDelay(250);
/* -------------- CALIBRATE TOP-LEFT --------------- */
passed = false;
while (!passed)
{
// Read X/Y depending on screen orientation
tsRenderCalibrationScreen(3, 3, 5);
_calibration.offsetLeft = orientation == LCD_ORIENTATION_LANDSCAPE ? tsReadY() : tsReadX();
_calibration.offsetTop = orientation == LCD_ORIENTATION_LANDSCAPE ? tsReadX() : tsReadY();
// Make sure values are in range
if (_calibration.offsetLeft < TS_CALIBRATION_OUTOFRANGE && _calibration.offsetTop < TS_CALIBRATION_OUTOFRANGE)
passed = true;
}
// Delay to avoid multiple touch events
systickDelay(250);
/* -------------- CALIBRATE BOTTOM-RIGHT --------------- */
passed = false;
while (!passed)
{
tsRenderCalibrationScreen(lcdGetWidth() - 4, lcdGetHeight() - 4, 5);
// Read X/Y depending on screen orientation
_calibration.offsetRight = orientation == LCD_ORIENTATION_LANDSCAPE ? TS_ADC_LIMIT - tsReadY() : TS_ADC_LIMIT - tsReadX();
_calibration.offsetBottom = orientation == LCD_ORIENTATION_LANDSCAPE ? TS_ADC_LIMIT - tsReadX() : TS_ADC_LIMIT - tsReadY();
// Redo test if value is out of range
if (_calibration.offsetRight < TS_CALIBRATION_OUTOFRANGE && _calibration.offsetBottom < TS_CALIBRATION_OUTOFRANGE)
passed = true;
}
// Delay to avoid multiple touch events
systickDelay(250);
/* -------------- CALIBRATE TOP-RIGHT --------------- */
passed = false;
while (!passed)
{
tsRenderCalibrationScreen(lcdGetWidth() - 4, 3, 5);
if (orientation == LCD_ORIENTATION_LANDSCAPE)
{
right2 = TS_ADC_LIMIT - tsReadY();
top2 = tsReadX();
}
else
{
right2 = tsReadX();
top2 = TS_ADC_LIMIT - tsReadY();
}
// Redo test if value is out of range
if (right2 < TS_CALIBRATION_OUTOFRANGE && top2 < TS_CALIBRATION_OUTOFRANGE)
passed = true;
}
// Average readings
_calibration.offsetRight = (_calibration.offsetRight + right2) / 2;
_calibration.offsetTop = (_calibration.offsetTop + top2) / 2;
// Delay to avoid multiple touch events
systickDelay(250);
/* -------------- CALIBRATE BOTTOM-LEFT --------------- */
passed = false;
while (!passed)
{
tsRenderCalibrationScreen(3, lcdGetHeight() - 4, 5);
if (orientation == LCD_ORIENTATION_LANDSCAPE)
{
left2 = tsReadY();
bottom2 = TS_ADC_LIMIT - tsReadX();
}
else
{
left2 = TS_ADC_LIMIT - tsReadX();
bottom2 = tsReadY();
}
// Redo test if value is out of range
if (left2 < TS_CALIBRATION_OUTOFRANGE && bottom2 < TS_CALIBRATION_OUTOFRANGE)
passed = true;
}
// Average readings
_calibration.offsetLeft = (_calibration.offsetLeft + left2) / 2;
_calibration.offsetBottom = (_calibration.offsetBottom + bottom2) / 2;
// Delay to avoid multiple touch events
systickDelay(250);
_calibration.divisorX = ((TS_ADC_LIMIT - (_calibration.offsetLeft + _calibration.offsetRight)) * 100) / lcdGetWidth();
_calibration.divisorY = ((TS_ADC_LIMIT - (_calibration.offsetTop + _calibration.offsetBottom)) * 100) / lcdGetHeight();
/* -------------- Persist Data --------------- */
// Persist data to EEPROM
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_LEFT, _calibration.offsetLeft);
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_RIGHT, _calibration.offsetRight);
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_TOP, _calibration.offsetTop);
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_BOT, _calibration.offsetBottom);
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_DIVX, _calibration.divisorX);
eepromWriteU16(CFG_EEPROM_TOUCHSCREEN_OFFSET_DIVY, _calibration.divisorY);
eepromWriteU8(CFG_EEPROM_TOUCHSCREEN_CALIBRATED, 1);
// Clear the screen
drawFill(COLOR_BLACK);
}
tsTouchError_t tsWaitForEvent(tsTouchData_t* data, uint32_t timeoutMS)
{
if (!_tsInitialised) tsInit();
uint32_t z1, z2;
uint32_t xRaw1, xRaw2, yRaw1, yRaw2;
z1 = z2 = 0;
// Handle timeout if delay > 0 milliseconds
if (timeoutMS)
{
uint32_t startTick = systickGetTicks();
// Systick rollover may occur while waiting for timeout
if (startTick > 0xFFFFFFFF - timeoutMS)
{
// Wait for timeout or touch event
while (z2 < CFG_TFTLCD_TS_THRESHOLD)
{
// Throw alert if timeout delay has been passed
if ((systickGetTicks() < startTick) && (systickGetTicks() >= (timeoutMS - (0xFFFFFFFF - startTick))))
{
return TS_ERROR_TIMEOUT;
}
tsReadZ(&z1, &z2);
}
}
// No systick rollover will occur ... calculate timeout the simple way
else
{
// Wait in infinite loop
while (z2 < CFG_TFTLCD_TS_THRESHOLD)
{
// Throw timeout if delay has been passed
if ((systickGetTicks() - startTick) > timeoutMS)
{
return TS_ERROR_TIMEOUT;
}
tsReadZ(&z1, &z2);
}
}
}
// No timeout requested ... wait forever
else
{
while (z2 < CFG_TFTLCD_TS_THRESHOLD)
{
tsReadZ(&z1, &z2);
}
}
// Get raw conversion results
// Each value is read twice and compared to avoid erroneous readings
xRaw1 = tsReadY(); // X and Y are reversed
xRaw2 = tsReadY(); // X and Y are reversed
yRaw1 = tsReadX(); // X and Y are reverse
yRaw2 = tsReadX(); // X and Y are reverse
// If both read attempts aren't identical, return mismatch error
if ((xRaw1 != xRaw2) || (yRaw1 != yRaw2))
{
return TS_ERROR_XYMISMATCH;
}
// Normalise X
data->x = ((xRaw1 - _calibration.offsetLeft > TS_ADC_LIMIT ? 0 : xRaw1 - _calibration.offsetLeft) * 100) / _calibration.divisorX;
if (data->x > lcdGetWidth() - 1) data->x = lcdGetWidth() - 1;
// Normalise Y
data->y = ((yRaw1 - _calibration.offsetTop > TS_ADC_LIMIT ? 0 : yRaw1 - _calibration.offsetTop) * 100) / _calibration.divisorY;
if (data->y > lcdGetHeight() - 1) data->y = lcdGetHeight() - 1;
// Indicate correct reading
return TS_ERROR_NONE;
}
tsTouchError_t tsRead(tsTouchData_t* data, uint8_t calibrating)
{
uint32_t x1, x2, y1, y2, z1, z2;
// Assign pressure levels regardless of touch state
tsReadZ(&z1, &z2);
data->z1 = z1;
data->z2 = z2;
data->xraw = 0;
data->yraw = 0;
data->xlcd = 0;
data->ylcd = 0;
// Abort if the screen is not being touched (0 levels reported)
if (z1 < _tsThreshhold)
{
data->valid = false;
return TS_ERROR_NONE;
}
// Get two X/Y readings and compare results
x1 = tsReadX();
x2 = tsReadX();
y1 = tsReadY();
y2 = tsReadY();
// Throw an error if both readings aren't identical
if (x1 != x2 || y1 != y2)
{
data->valid = false;
data->xraw = x1;
data->yraw = y1;
return TS_ERROR_XYMISMATCH;
}
// X/Y seems to be valid and reading has been confirmed twice
data->xraw = x1;
data->yraw = y1;
// Convert x/y values to pixel location with matrix multiply
tsPoint_t location, touch;
touch.x = x1;
touch.y = y1;
// Only calculate the relative LCD value if this isn't for calibration
if (!calibrating)
{
getDisplayPoint( &location, &touch, &_tsMatrix) ;
data->xlcd = location.x;
data->ylcd = location.y;
}
else
{
// Assign some false values, but only xraw and yraw are
// used for calibration
data->xlcd = 0;
data->ylcd = 0;
}
data->valid = true;
return TS_ERROR_NONE;
}