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//******************************************************************************
// @file XPT2046.cpp
// @author Nicolai Shlapunov
//
// @details DevCore: XPT2046 Low Level Driver Class, implementation
//
// @copyright Copyright (c) 2016, Devtronic & Nicolai Shlapunov
// All rights reserved.
//
// @section SUPPORT
//
// Devtronic invests time and resources providing this open source code,
// please support Devtronic and open-source hardware/software by
// donations and/or purchasing products from Devtronic.
//
//******************************************************************************
// *****************************************************************************
// *** Includes ************************************************************
// *****************************************************************************
#include <XPT2046.h>
// *****************************************************************************
// *** Init touchscreen ****************************************************
// *****************************************************************************
void XPT2046::Init(void)
{
// Pull down CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_RESET);
// Send ON command
SpiWrite(TON);
// Send empty byte for skip answer
SpiWrite(EMP);
// Send empty byte for skip answer
SpiWrite(EMP);
// Pull up CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_SET);
}
// *****************************************************************************
// *** If touched - return true. *******************************************
// *****************************************************************************
bool XPT2046::IsTouch(void)
{
// Check T_IRQ input and return state
return(HAL_GPIO_ReadPin(T_IRQ_GPIO_Port, T_IRQ_Pin) == GPIO_PIN_RESET);
}
// *****************************************************************************
// *** Get X and Y coordinates. If touched - return true. ******************
// *****************************************************************************
bool XPT2046::GetRawXY(int32_t& x, int32_t& y)
{
// Return value
bool ret = false;
// If touch present
if(HAL_GPIO_ReadPin(T_IRQ_GPIO_Port, T_IRQ_Pin) == GPIO_PIN_RESET)
{
// Pull down CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_RESET);
// Request X coordinate
SpiWrite(CHX);
// Receive High byte for X
x = SpiWriteRead(EMP) << 8;
// Receive Low byte for X
x |= SpiWriteRead(EMP);
// Shift, because result have only 12 bits, 3 because answer started from
// second rise edge
x >>= 3;
// Pull up CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_SET);
// Pull down CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_RESET);
// Request Y coordinate
SpiWrite(CHY);
// Receive High byte for Y
y = SpiWriteRead(EMP) << 8;
// Receive Low byte for Y
y |= SpiWriteRead(EMP);
// Shift, because result have only 12 bits, 3 because answer started from
// second rise edge
y >>= 3;
// Pull up CS
HAL_GPIO_WritePin(TOUCH_CS_GPIO_Port, TOUCH_CS_Pin, GPIO_PIN_SET);
// Touch present
ret = true;
}
// Return result
return ret;
}
// *****************************************************************************
// *** Get X and Y coordinates. If touched - return true. ******************
// *****************************************************************************
bool XPT2046::GetXY(int32_t& x, int32_t& y)
{
// Return value
bool ret = GetRawXY(x, y);
// If touch present
if(ret)
{
// Calculate X
x = ((x * COEF) / kx) + bx;
// Calculate Y
y = ((y * COEF) / ky) + by;
}
// Return touch state
return ret;
}
// *****************************************************************************
// *** SetCalibrationConsts ************************************************
// *****************************************************************************
void XPT2046::SetCalibrationConsts(int32_t nkx, int32_t nky, int32_t nbx, int32_t nby)
{
// Save calibration constants
kx = nkx;
ky = nky;
bx = nbx;
by = nby;
}
// *****************************************************************************
// *** Write byte to SPI ***************************************************
// *****************************************************************************
inline void XPT2046::SpiWrite(uint8_t c)
{
// Call HAL function for send byte by SPI
(void) HAL_SPI_Transmit(hspi, &c, sizeof(c), 1U);
}
// *****************************************************************************
// *** Write and read byte to/from SPI *************************************
// *****************************************************************************
inline uint8_t XPT2046::SpiWriteRead(uint8_t c)
{
// Temporary variable for receive byte
uint8_t rcv;
// Call HAL function for send/receive byte by SPI
(void) HAL_SPI_TransmitReceive(hspi, &c, &rcv, sizeof(uint8_t), 1U);
// Return received byte
return rcv;
}
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