dc550_hookswitchmonitor.c

一款经典的数字电话设计资料

/*****************************************************************************/
/*  CONFIDENTIAL                                                             */
/*  Sigpro Copyright 2003, All rights reserved                               */
/*****************************************************************************/
/*  CLIENT:  Telematrix                                                      */
/*  PROJECT: DC550 Digital Centrex Phone                                     */
/*  FILE:    dc550_hookswitchmonitor.c                                       */
/*****************************************************************************/
/*  This file contains the code used to detect and debounce the hookswitch   */
/*  state.                                                                   */
/*****************************************************************************/

#include "dc550_hookswitchmonitor.h"
// #include "dc550_usartdriver.h"

/******************************************************************************
 *  LOCAL CONSTANTS AND DATA TYPES
 *****************************************************************************/
typedef enum enum_HS_STATE {
    HS_IDLE=0, HS_DEBOUNCING_OFF, HS_OFF, HS_DEBOUNCING_ON
} HS_STATE;

struct str_hsTaskData {
  HS_STATE    state;
  signed char ctr;
};

/******************************************************************************
 *  STATIC VARIABLES
 *****************************************************************************/
static struct str_hsTaskData hsTaskData;


/******************************************************************************
 *  FUNCTION: void hookswitchmonitor_init(void)
 ******************************************************************************
 *  DESCRIPTION:
 *  This function is called to initialize the hookswitch monitor task.  The
 *  hookswitch state will be initially set to on-hook but the actual state
 *  must be debounced which will require several iterations of the exec()
 *  function before the hookswitch state can be verified.
 *****************************************************************************/
void hookswitchmonitor_init(void)
{
    /* Initialize global/static variables */
    hsTaskData.state = HS_IDLE;
    hsTaskData.ctr = 0;

    /* Initialize port pin of interest */
    HOOKSWITCH_DIR &= ~(HOOKSWITCH_MSK);

    /* Read the current status of the hook switch */
    hsTaskData.state = (((HOOKSWITCH_IN & HOOKSWITCH_MSK) == 0) ?
                          HS_OFF : HS_IDLE);
}

/******************************************************************************
 *  FUNCTION: void hookswitchmonitor_exec(void)
 ******************************************************************************
 *  DESCRIPTION:
 *  This function is called to execute the hookswitch monitor task.
 *****************************************************************************/
void hookswitchmonitor_exec(void)
{
    unsigned int hookState;

    /* Read the current status of the hook switch */
    hookState = (((HOOKSWITCH_IN & HOOKSWITCH_MSK) == 0) ?
                      HOOKSTATE_UP : HOOKSTATE_DOWN);

    /* Phone is Off-Hook */
    if (hookState == HOOKSTATE_UP) {

        /* If was on-hook last time, zero the counter and start over */
        if ( (hsTaskData.state == HS_DEBOUNCING_ON) ||
             (hsTaskData.state == HS_IDLE) ) {
            hsTaskData.ctr = 0;
            if (hsTaskData.state == HS_DEBOUNCING_ON)
                hsTaskData.state = HS_OFF;
        }

        /* Still debouncing... */
        if ( (hsTaskData.state != HS_OFF) &&
             (hsTaskData.ctr < HS_OFF_MAXCNT) ) {

            /* Increment debounce counter */
            hsTaskData.ctr++;

            /* Set state to debouncing down */
            hsTaskData.state = HS_DEBOUNCING_OFF;

            /* Is the phone solid off-hook yet? */
            if (hsTaskData.ctr == HS_OFF_MAXCNT) {
 
                /* Set our state to HS_OFF */
                hsTaskData.state = HS_OFF;
                // dc550_printf("\r\nOFF HOOK");
            }
        }
    }

    /* Phone is On-Hook */
    else {

        /* If was off-hook last time, zero the counter and start over */
        if ( (hsTaskData.state == HS_DEBOUNCING_OFF) ||
             (hsTaskData.state == HS_OFF) ) {
            hsTaskData.ctr = 0;
            if (hsTaskData.state == HS_DEBOUNCING_OFF)
                hsTaskData.state = HS_IDLE;
        }

        /* Still debouncing... */
        if ( (hsTaskData.state != HS_IDLE) &&
             (hsTaskData.ctr < HS_ON_MAXCNT) ) {

            /* Increment debounce counter */
            hsTaskData.ctr++;

            /* Set state to debouncing on-hook */
            hsTaskData.state = HS_DEBOUNCING_ON;

            /* Is the phone solid on-hook yet? */
            if (hsTaskData.ctr == HS_ON_MAXCNT) {

                /* Set our state to HS_IDLE */
                hsTaskData.state = HS_IDLE;
                // dc550_printf("\r\nON HOOK");

            }
        }
    }
}



/******************************************************************************
 *  FUNCTION: unsigned int hookswitchmonitor_gethookswitchstate(void)
 ******************************************************************************
 *  DESCRIPTION:
 *  This accessor function returns the last debounced state of the hookswitch.
 *****************************************************************************/
unsigned int hookswitchmonitor_gethookswitchstate(void)
{

    switch (hsTaskData.state) {
    case (HS_IDLE):
    case (HS_DEBOUNCING_OFF):
      return (HOOKSTATE_DOWN);

    case (HS_OFF):
    case (HS_DEBOUNCING_ON):
      return (HOOKSTATE_UP);

    default:
      return (HOOKSTATE_DOWN);
    }
}