pimoroni-pico/drivers/trackball/trackball.hpp

#pragma once

#include "hardware/i2c.h"
#include "hardware/gpio.h"

namespace pimoroni {

  class Trackball {
    //--------------------------------------------------
    // Constants
    //--------------------------------------------------
  public:
    static const uint8_t DEFAULT_I2C_ADDRESS        = 0x0A;
    static const uint8_t I2C_ADDRESS_ALTERNATIVE    = 0x0B;
    static const uint8_t DEFAULT_SDA_PIN            = 20;
    static const uint8_t DEFAULT_SCL_PIN            = 21;
    static const uint8_t DEFAULT_INT_PIN            = 22;
    static const uint32_t DEFAULT_TIMEOUT           = 5;
    static const uint8_t PIN_UNUSED                 = UINT8_MAX;

  private:
    static const uint16_t CHIP_ID = 0xBA11;
    static const uint8_t VERSION = 1;


    //--------------------------------------------------
    // Substructures
    //--------------------------------------------------
  public:
    struct State {
      uint8_t left;
      uint8_t right;
      uint8_t up;
      uint8_t down;
      bool sw_changed;
      bool sw_pressed;
    };


    //--------------------------------------------------
    // Variables
    //--------------------------------------------------
  private:
    i2c_inst_t *i2c     = i2c0;

    // interface pins with our standard defaults where appropriate
    int8_t address      = DEFAULT_I2C_ADDRESS;
    int8_t sda          = DEFAULT_SDA_PIN;
    int8_t scl          = DEFAULT_SCL_PIN;
    int8_t interrupt    = DEFAULT_INT_PIN;
    uint32_t timeout    = DEFAULT_TIMEOUT;


    //--------------------------------------------------
    // Constructors/Destructor
    //--------------------------------------------------
  public:
    Trackball() {};

    Trackball(uint8_t address) :
      address(address) {}

    Trackball(i2c_inst_t *i2c, uint8_t address, uint8_t sda, uint8_t scl, uint8_t interrupt = PIN_UNUSED, uint32_t timeout = DEFAULT_TIMEOUT) :
      i2c(i2c), address(address), sda(sda), scl(scl), interrupt(interrupt), timeout(timeout) {}


    //--------------------------------------------------
    // Methods
    //--------------------------------------------------
  public: 
    bool init();

    i2c_inst_t* get_i2c() const;
    int get_sda() const;
    int get_scl() const;
    int get_int() const;

    void change_address(uint8_t new_address);
        
    void enable_interrupt(bool use_interrupt = true);
    bool get_interrupt();
    void set_rgbw(uint8_t r, uint8_t g, uint8_t b, uint8_t w);
    void set_red(uint8_t value);
    void set_green(uint8_t value);
    void set_blue(uint8_t value);
    void set_white(uint8_t value);
    State read();

  private:
    uint8_t i2c_reg_read_uint8(uint8_t reg);
    void i2c_reg_write_uint8(uint8_t reg, uint8_t value);

    void wait_for_flash();

    uint32_t millis();
  };

}