TSC2046.hpp

/*
 * TSC2046.hpp
 *
 * STM32 HAL port of Adafruit's TSC2046 resistive touchscreen controller
 * driver -- reads raw touch X/Y coordinates and pressure over SPI.
 *
 * Adapted from Adafruit_TSC2046
 * (https://github.com/adafruit/Adafruit_TSC2046, MIT License, Copyright (c)
 * 2023 Adafruit Industries, Copyright (c) 2023 Mikaela Szekely) as a design
 * reference for the command byte layout, differential/single-ended read
 * modes, and pressure formula -- this is an independent STM32 HAL
 * implementation built on STM32BusIO, not a direct port of Adafruit's
 * Arduino source.
 *
 *  Created on: Sep 15, 2026
 *      Author: johng
 */
 
#ifndef TSC2046_TSC2046_HPP_
#define TSC2046_TSC2046_HPP_
 
#include "STM32SPIDevice.hpp"
 
struct TSC2046TouchPoint {
    int16_t x;       
    int16_t y;       
    float pressure;  
};
 
class TSC2046 {
public:
    TSC2046(SPI_HandleTypeDef *hspi, GPIO_TypeDef *csPort, uint16_t csPin);
 
    void begin(uint32_t xPlateResistance = 400);
 
    void setVRef(float vref);
 
    void setTouchedThreshold(float touchedThresholdOhms);
 
    TSC2046TouchPoint getPoint();
 
    bool isTouched();
 
    void enableInterrupts(bool enable);
 
    float readTemperatureC();
 
    float readTemperatureF();
 
    float readBatteryVoltage();
 
    float readAuxiliaryVoltage();
 
private:
    uint16_t readCoord(uint8_t channelSelect);
    uint16_t readExtra(uint8_t channelSelect);
    float effectiveVRef();
    float readTemperatureKelvin();
    static uint16_t extractTwelveBitValue(uint32_t registerValue);
 
    STM32SPIDevice _spiDevice;
    uint32_t _xPlateResistance;
    float _vref;
    float _touchedThreshold;
    bool _interruptsEnabled;
};
 
#endif /* TSC2046_TSC2046_HPP_ */