VLCD.hh

Go to the documentation of this file.

#ifndef COSA_VLCD_HH
#define COSA_VLCD_HH

#include "Cosa/LCD.hh"
#include "Cosa/TWI.hh"

class VLCD : public LCD::Device, private TWI::Driver {
public:
  // Display protocol version (valid after initialization, begin())
  uint8_t MAJOR;
  uint8_t MINOR;

  // Display width (characters per line) and height (lines)
  uint8_t WIDTH;
  uint8_t HEIGHT;

  VLCD(uint8_t addr = 0x5a) :
    LCD::Device(),
    TWI::Driver(addr),
    MAJOR(0),
    MINOR(0),
    WIDTH(0),
    HEIGHT(0)
  {}

  virtual bool begin();

  virtual bool end();

  virtual void backlight_on();

  virtual void backlight_off();

  virtual void display_on();

  virtual void display_off();

  virtual void display_clear();

  virtual void set_cursor(uint8_t x, uint8_t y);

  virtual int putchar(char c);

  using IOStream::Device::write;

  virtual int write(const void* buf, size_t size);

  class Slave : public TWI::Slave {
    friend class VLCD;
  public:
    // Max size of buffer
    static const uint8_t BUF_MAX = 40;

    Slave(LCD::Device* lcd, uint8_t addr = 0x5a) :
      TWI::Slave(addr),
      m_lcd(lcd)
    {
      write_buf(m_buf, sizeof(m_buf));
      read_buf(m_buf, sizeof(m_buf));
    }

    virtual void on_request(void* buf, size_t size);

  private:
    // Version code
    static const uint8_t MAJOR = 1;
    static const uint8_t MINOR = 0;

    // Command prefix byte
    static const uint8_t COMMAND = 255;

    // Command codes
    enum {
      BACKLIGHT_OFF_CMD = 0,
      BACKLIGHT_ON_CMD,
      DISPLAY_OFF_CMD,
      DISPLAY_ON_CMD,
      INIT_CMD = 0xff
    } __attribute__((packed));

    // Buffer for transactions (max string write)
    uint8_t m_buf[BUF_MAX];

    // The actual LCD implementation
    LCD::Device* m_lcd;
  };

private:
  // Version information
  struct info_t {
    uint8_t major;
    uint8_t minor;
    uint8_t width;
    uint8_t height;
  };

  void write(uint8_t cmd);
};

#endif