/*_____ I N C L U D E S ____________________________________________________*/

#include "config.h"                         /* lib configuration header */
#include "include/kbd_drv.h"                        /* Keyboard driver definition */


/*_____ M A C R O S ________________________________________________________*/


/*_____ D E F I N I T I O N ________________________________________________*/


/*_____ D E C L A R A T I O N ______________________________________________*/

static  void    kbd_set_prio (Byte);


/*F**************************************************************************
* NAME: kbd_init
*----------------------------------------------------------------------------
* PARAMS:
*
* return:
*----------------------------------------------------------------------------
* PURPOSE:
*   Keyboard initialisation function
*----------------------------------------------------------------------------
* EXAMPLE:
*----------------------------------------------------------------------------
* NOTE:
*----------------------------------------------------------------------------
* REQUIREMENTS:
* ram/xram:
* cycle:
* stack:
* code:
*****************************************************************************/
Byte kbd_init (void)
{
  kbd_set_prio(KBD_PRIO);

  KBSTA = KBSTA;                            /* clear pending interrupt */
  P_KBD |= MSK_COL;                         /* all columns inactive */
  KBCON = KB_STD;                         /* detect 1 to 0 transition */
  P_KBD &= MSK_STD;                       /* 0 on all columns */
  return ON;                              /* Keyboard not locked */
}


/*F**************************************************************************
* NAME: kbd_set_prio
*----------------------------------------------------------------------------
* PARAMS:
*
* return:
*----------------------------------------------------------------------------
* PURPOSE:
*   Set the keyboard interface priority interrupt
*----------------------------------------------------------------------------
* EXAMPLE:
*----------------------------------------------------------------------------
* NOTE:
*----------------------------------------------------------------------------
* REQUIREMENTS:
* ram/xram:
* cycle:
* stack:
* code:
*****************************************************************************/
void kbd_set_prio (Byte priority)
{
  if ((priority == 1) || (priority == 3))   /* set LSB priority bit */
  {
    IPL1 |=  MSK_EKB;
  }
  if ((priority == 2) || (priority == 3))   /* set MSB priority bit */
  {
    IPH1 |= MSK_EKB;
  }
}


/*F**************************************************************************
* NAME: kbd_decode
*----------------------------------------------------------------------------
* PARAMS:
*
* return:
*   Decoded key pressed
*----------------------------------------------------------------------------
* PURPOSE:
*   Decode the key that generated an IT
*----------------------------------------------------------------------------
* EXAMPLE:
*----------------------------------------------------------------------------
* NOTE:
*----------------------------------------------------------------------------
* REQUIREMENTS:
* ram/xram:
* cycle:
* stack:
* code:
*****************************************************************************/
Byte kbd_decode (void)
{
Byte key;

  P_KBD |= MSK_COL;                         /* all columns inactive */

  /* COL3 = 0;                               COL3 test (always 0) */
  key = (P_KBD & MSK_PKB);
  if (key != NK_COL3)
  {
    KBCON |= (KBSTA << 4);                   /*detect 0 to 1 transition */
    P_KBD &= MSK_STD;                       /* 0 on all columns */
    KBSTA = KBSTA;                          /* clear pending interrupt */
    return (key);
  }

  COL2 = 0;                                 /* COL2 test */
  key = (P_KBD & MSK_PKB);
  if (key != NK_COL2)
  {
    KBCON |= (KBSTA << 4);                   /*detect 0 to 1 transition */
    P_KBD &= MSK_STD;                       /* 0 on all columns */
    KBSTA = KBSTA;                          /* clear pending interrupt */
    return (key);
  }

  COL1 = 0;                                 /* COL1 test */
  key = (P_KBD & MSK_PKB);
  if (key != NK_COL1)
  {
    KBCON |= (KBSTA << 4);                   /*detect 0 to 1 transition */
    P_KBD &= MSK_STD;                       /* 0 on all columns */
    KBSTA = KBSTA;                          /* clear pending interrupt */
    return (key);
  }

  COL0 = 0;                                 /* COL0 test */
  key = (P_KBD & MSK_PKB);
  if (key != NK_COL0)
  {
    KBCON |= (KBSTA << 4);                   /*detect 0 to 1 transition */
    KBSTA = KBSTA;                          /* clear pending interrupt */
    return (key);
  }

  KBCON = KB_STD;                           /* detect 1 to 0 transition */
  P_KBD &= MSK_STD;                         /* 0 on all columns */
  KBSTA = KBSTA;                            /* clear pending interrupt */
  return NO_KEY;
}