Adafruit_TSC2046.h

Go to the documentation of this file.

#ifndef ADA_TSC2046_H
#define ADA_TSC2046_H

#include "Arduino.h"
#include "Print.h"
#include <Adafruit_BusIO_Register.h>
#include <Adafruit_SPIDevice.h>
#include <stdint.h>

class TSPoint {
public:
  TSPoint(int16_t x, int16_t y, float z);

  int16_t x;

  int16_t y;

  float z;

  float xPercent();

  float yPercent();
};

class Adafruit_TSC2046 {
public:
  ~Adafruit_TSC2046();

  void begin(int spiChipSelect, SPIClass *the_spi = &SPI,
             uint32_t xResistance = 400,
             uint32_t spiFrequency = 2L * 1000L * 1000L);

  void setVRef(float vRef);

  void setTouchedThreshold(float rTouchThreshold);

  TSPoint getPoint();

  bool isTouched();

  void enableInterrupts(bool enable);

  float readTemperatureC();

  float readTemperatureF();

  float readBatteryVoltage();

  float readAuxiliaryVoltage();

  float effectiveVRef();

private:
  SPIClass *_spi;
  Adafruit_SPIDevice *_spiDev;
  int _spiCS;
  int64_t _spiFrequency;
  uint32_t _xResistance;

  // NOTE(Qyriad): In my testing, the absolute most delicate touch where the X
  // and Y coordinate values were not completely nonsensical had R_TOUCH at
  // about 5.7kΩ (and even then the X and Y coordinates were still fairly
  // off), and every complete false positive was above 100kΩ. To be on the
  // safe side we'll use 100kΩ as the default threshold.
  float _touchedThreshold = 100000.f;

  bool _interruptsEnabled = true;
  float _vRef;

  float readTemperatureK();

  // Performs a 12-bit differential reference mode read,
  // used for coordinate reads.
  uint16_t readCoord(uint8_t channelSelect);

  // Performs a 12-bit single-ended reference mode read,
  // used for non-coordinate reads.
  uint16_t readExtra(uint8_t channelSelect);

  static uint16_t parse12BitValue(uint8_t spiUpperByte, uint8_t spiLowerByte);
};

// NOTE: Bitfield structs like these are not generally portable as the union'd
// word can be different on machines of different endianness. Normally we would
// detect a big endian platform with #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__,
// and #error in that case. However, here, our struct is only 1 byte wide, so
// byte order shouldn't come into play.
union Command {
  // NOTE: The order these are defined in is the opposite as they appear in the
  // datasheet, because bitfield structs are least-significant-field first.
  struct {
    uint8_t enableOrIdleADC : 1;

    uint8_t enableInternalVRef : 1;

    uint8_t singleEndedRef : 1;

    uint8_t use8BitConv : 1;

    uint8_t addr : 3;

    uint8_t start : 1;
  };
  uint8_t word;
};

#endif