//----------------------------------------------------------------------------

//Encoder support module

//----------------------------------------------------------------------------

#include <Main.h>
#include <Encoder.h>

//------------------------------ Constants: ----------------------------------


#define ENCDEB  300            //encoder debounce delay, uS
#define SWBDEB   30            //button debounce delay, mS
#define SWBHLD 1000            //button hold delay, mS
#define ENC_TMV 150            //encoder velocity measure interval, mS
#define ENC_V     2            //threshold velocity, steps per ENC_TMV

#define EF1    0x01            //encoder F1 mask
#define EF2    0x02            //encoder F2 mask

enum
{
  ES0, ES1, ES3, ES2           //encoder sequential states
};

//------------------------------ Variables: ----------------------------------

static char EncPre;            //previous encoder state
static char EncPpe;            //pre-pre encoder state
static bool BtnPre;            //previous button state
static char Msg;               //encoder message

//------------------------- Function prototypes: -----------------------------

char Enc_Scan(void);           //scan encoder
bool Btn_Scan(void);           //scan button

//---------------------------- Encoder init: ---------------------------------

void Enc_Init(void)
{
  Msg = MSG_NOP;               //no message
  EncPre = Enc_Scan();         //scan encoder and store state
  EncPpe = EncPre;             //store pre-pre state
  BtnPre = 0;                  //allow power-up button hold
}

//------------------------- Get encoder message: -----------------------------

char Enc_Get(void)
{
  return(Msg);
}

//------------------------- Set encoder message: -----------------------------

void Enc_Set(char msg)
{
  Msg = msg;
}

//---------------------------- Scan encoder: ---------------------------------

char Enc_Scan(void)
{
  char n = 0;
  if(Pin_ENC_F1) n |= EF1;     //check F1 line
  if(Pin_ENC_F2) n |= EF2;     //check F2 line
  return(n);
}

//---------------------------- Scan button: ----------------------------------

bool Btn_Scan(void)
{
  return(!Pin_BTN);            //check button state
}

//-------------------------- Encoder processing: -----------------------------

//Result placed in Msg as encoder message.
//Message codes see in file Encoder.h.

void Enc_Exe(bool t)
{
  static int DbncTimer = 0;
  static int HoldTimer = 0;
  static int EncTimer = ms2sys(ENC_TMV);
  static char EncV = 0;
  static char EncS = 0;
  //process timers:
  if(t)
  {
    if(DbncTimer) DbncTimer--;
    if(HoldTimer) HoldTimer--;
    if(EncTimer)  EncTimer--;
    else
    {
#ifdef VAR_ENC
      EncV = EncS;
#endif
      EncS = 0;
      EncTimer = ms2sys(ENC_TMV);
    }
    if(DbncTimer == 1)
    {
      if(BtnPre)
      {
        Msg = MSG_KDN;           //button press
        HoldTimer = ms2sys(SWBHLD);
        return;
      }
      if(!BtnPre && HoldTimer)
      {
        Msg = MSG_KUP;           //button release
        HoldTimer = 0;
        return;
      }
    }
    if(HoldTimer == 1)
    {
      Msg = MSG_KHD;             //button hold
      return;
    }
  }
  
  //scan button:
  bool BtnTmp = Btn_Scan();      //scan button
  if(BtnTmp != BtnPre)
  {
    DbncTimer = ms2sys(SWBDEB);  //reload debounce timer
    BtnPre = BtnTmp;             //save new state
  }
  
  //scan encoder:
  char EncTmp = Enc_Scan();      //scan encoder and store result
  Delay_us(ENCDEB);              //debounce delay for encoder
  char EncNew = Enc_Scan();      //scan encoder one more time
  if(EncNew != EncTmp) return;   //bounce in progress, return
  if(EncNew == EncPre) return;   //no changes, return

  EncTmp = EncPpe;               //pre-pre state
  EncPpe = EncPre;               //pre-sate
  EncPre = EncNew;               //new state

  if(EncNew == ES2 && EncPpe == ES1 && EncTmp == ES0)
  {
    EncS++;
    if(EncV > ENC_V)
      Msg = MSG_FDEC;            //fast decrement message
        else Msg = MSG_DEC;      //decrement message
    return;
  }
  if(EncNew == ES2 && EncPpe == ES3 && EncTmp == ES0)
  {
    EncS++;
    if(EncV > ENC_V)
      Msg = MSG_FINC;            //fast increment message
        else Msg = MSG_INC;      //increment message
    return;
  }
}

//----------------------------------------------------------------------------