Electronics_Projects_2018/Air_Quality_Sensor_PPD42/resources/MSP-EXP430G2 Software Examples/Source/430BOOST-SENSE1/CapTouch_BoosterPack_UserExperience/CapacitiveTouchLibrary/CTS_Layer.c

/*******************************************************************************
 * CTS_HAL.c - defines functions called by application as well as 
 *                   functions for information processing
 *
 *  Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/ 
 * 
 *  Redistribution and use in source and binary forms, with or without 
 *  modification, are permitted provided that the following conditions 
 *  are met:
 *
 *    Redistributions of source code must retain the above copyright 
 *    notice, this list of conditions and the following disclaimer.
 *
 *    Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the 
 *    documentation and/or other materials provided with the   
 *    distribution.
 *
 *    Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 ******************************************************************************/

/***************************************************************************//**
 * @file   CTS_HAL.c
 *
 * @brief       
 *
 * @par    Project:
 *             MSP430 Capacitive Touch Library 
 *
 * @par    Developed using:
 *             IAR Version : 5.10.6 [Kickstart] (5.10.6.30180)
 *             CCS Version : 4.2.1.00004, w/support for GCC extensions (--gcc)
 *
 * @version     1.0.0 Initial Release
 *
 * @par    Supported API Calls:
 *              - TI_CAPT_Init_Baseline()
 *              - TI_CAPT_Update_Baseline()
 *              - TI_CAPT_Reset_Tracking()
 *              - TI_CAPT_Update_Tracking_DOI()
 *              - TI_CAPT_Update_Tracking_Rate()
 *              - TI_CAPT_Update_Baseline()
 *              - TI_CAPT_Raw()
 *              - TI_CAPT_Custom()
 *              - TI_CAPT_Button()
 *              - TI_CAPT_Buttons()
 *              - TI_CAPT_Slider()
 *              - TI_CAPT_Wheel()
 ******************************************************************************/

#include "CTS_Layer.h"
#include <stdlib.h>

// Global variables for sensing
#ifdef TOTAL_NUMBER_OF_ELEMENTS
uint16_t baseCnt[TOTAL_NUMBER_OF_ELEMENTS];
#ifdef RAM_FOR_FLASH
uint16_t measCnt[MAXIMUM_NUMBER_OF_ELEMENTS_PER_SENSOR];
#endif
uint16_t ctsStatusReg = (DOI_INC+TRADOI_FAST+TRIDOI_SLOW);
#endif

/***************************************************************************//**
 * @addtogroup CTS_API
 * @{ 
 ******************************************************************************/


/***************************************************************************//**
 * @brief   Measure the capacitance of each element within the Sensor
 * 
 *          This function selects the appropriate HAL to perform the capacitance
 *          measurement based upon the halDefinition found in the sensor 
 *          structure. 
 *          The order of the elements within the Sensor structure is arbitrary 
 *          but must be consistent between the application and configuration. 
 *          The first element in the array (counts) corresponds to the first 
 *          element within the Sensor structure.
 * @param   groupOfElements Pointer to Sensor structure to be measured
 * @param   counts Address to where the measurements are to be written
 * @return  none
 ******************************************************************************/
void TI_CAPT_Raw(const struct Sensor* groupOfElements, uint16_t * counts)
{
#ifdef RO_COMPAp_TA0_WDTp
    if(groupOfElements->halDefinition == RO_COMPAp_TA0_WDTp)
    {
      TI_CTS_RO_COMPAp_TA0_WDTp_HAL(groupOfElements, counts);
    }
#endif

#ifdef fRO_COMPAp_TA0_SW
    if(groupOfElements->halDefinition == fRO_COMPAp_TA0_SW)
    {
      TI_CTS_fRO_COMPAp_TA0_SW_HAL(groupOfElements, counts);
    }
#endif  

#ifdef fRO_COMPAp_SW_TA0
    if(groupOfElements->halDefinition == fRO_COMPAp_SW_TA0)
    {
      TI_CTS_fRO_COMPAp_SW_TA0_HAL(groupOfElements, counts);
    }
#endif  

#ifdef RO_COMPAp_TA1_WDTp
    if(groupOfElements->halDefinition == RO_COMPAp_TA1_WDTp)
    {
      TI_CTS_RO_COMPAp_TA1_WDTp_HAL(groupOfElements, counts);
    }
#endif

#ifdef fRO_COMPAp_TA1_SW
    if(groupOfElements->halDefinition == fRO_COMPAp_TA1_SW)
    {
      TI_CTS_fRO_COMPAp_TA1_SW_HAL(groupOfElements, counts);
    }
#endif  

#ifdef RC_PAIR_TA0
    if(groupOfElements->halDefinition == RC_PAIR_TA0)
    {
      TI_CTS_RC_PAIR_TA0_HAL(groupOfElements, counts);   // Measure all sensors
    }
#endif

#ifdef RO_PINOSC_TA0_WDTp 
    if(groupOfElements->halDefinition == RO_PINOSC_TA0_WDTp)
    {
      TI_CTS_RO_PINOSC_TA0_WDTp_HAL(groupOfElements, counts);
    }
#endif

#ifdef RO_PINOSC_TA0 
    if(groupOfElements->halDefinition == RO_PINOSC_TA0)
    {
      TI_CTS_RO_PINOSC_TA0_HAL(groupOfElements, counts);
    }
#endif

#ifdef fRO_PINOSC_TA0_SW
    if(groupOfElements->halDefinition == fRO_PINOSC_TA0_SW)
    {
      TI_CTS_fRO_PINOSC_TA0_SW_HAL(groupOfElements, counts);   // Measure all sensors
    }
#endif

#ifdef RO_COMPB_TA0_WDTA
    if(groupOfElements->halDefinition == RO_COMPB_TA0_WDTA)
    {
      TI_CTS_RO_COMPB_TA0_WDTA_HAL(groupOfElements, counts);
    }
#endif  

#ifdef fRO_COMPB_TA0_SW
    if(groupOfElements->halDefinition == fRO_COMPB_TA0_SW)
    {
      TI_CTS_fRO_COMPB_TA0_SW_HAL(groupOfElements, counts);
    }
#endif

#ifdef RO_COMPB_TA1_WDTA
    if(groupOfElements->halDefinition == RO_COMPB_TA1_WDTA)
    {
      TI_CTS_RO_COMPB_TA1_WDTA_HAL(groupOfElements, counts);
    }
#endif      

#ifdef fRO_COMPB_TA1_SW
    if(groupOfElements->halDefinition == fRO_COMPB_TA1_SW)
    {
      TI_CTS_fRO_COMPB_TA1_SW_HAL(groupOfElements, counts);
    }
#endif  
}

#ifdef TOTAL_NUMBER_OF_ELEMENTS
/***************************************************************************//**
 * @brief   Make a single capacitance meausrment to initialize baseline tracking
 * @param   groupOfElements Pointer to Sensor structure to be measured
 * @return  none
 ******************************************************************************/
void TI_CAPT_Init_Baseline(const struct Sensor* groupOfElements)
{
    TI_CAPT_Raw(groupOfElements, &baseCnt[groupOfElements->baseOffset]);
}

/***************************************************************************//**
 * @brief   Update baseline tracking by averaging several measurements
 * @param   groupOfElements Pointer to Sensor structure to be measured
 * @param   numberofAverages Number of measurements to be averaged
 * @return  none
 ******************************************************************************/
void TI_CAPT_Update_Baseline(const struct Sensor* groupOfElements, uint8_t numberOfAverages)
{
	uint8_t i,j;
    #ifndef RAM_FOR_FLASH
	uint16_t *measCnt;
    measCnt = (uint16_t *)malloc(groupOfElements->numElements * sizeof(uint16_t));
    if(measCnt ==0)
    {
        while(1);
    }
    #endif
    for(j=0; j < numberOfAverages; j++)
    {
        for(i=0; i < groupOfElements->numElements; i++)
        {
            TI_CAPT_Raw(groupOfElements, measCnt);
            baseCnt[i+groupOfElements->baseOffset] = measCnt[i]/2 + baseCnt[i+groupOfElements->baseOffset]/2;
        }
    }
    #ifndef RAM_FOR_FLASH
    free(measCnt);
    #endif
}

/***************************************************************************//**
 * @brief   Reset the Baseline Tracking algorithm to the default state
 * @param   none
 * @return  none
 ******************************************************************************/
void TI_CAPT_Reset_Tracking(void)
{
    ctsStatusReg = (DOI_INC+TRADOI_FAST+TRIDOI_SLOW);
}

/***************************************************************************//**
 * @brief   Update the Baseline Tracking algorithm Direction of Interest
 * @param   direction Direction of increasing or decreasing capacitance
 * @return  none
 ******************************************************************************/
void TI_CAPT_Update_Tracking_DOI(uint8_t direction)
{
	if(direction)
	{
		ctsStatusReg |= DOI_INC;
	}
	else
	{
		ctsStatusReg &= ~DOI_INC;
	}
}

/***************************************************************************//**
 * @brief   Update the baseling tracking algorithm tracking rates
 * @param   rate Rate of tracking changes in and against direction of intrest
 * @return  none
 ******************************************************************************/
void TI_CAPT_Update_Tracking_Rate(uint8_t rate)
{
  ctsStatusReg &= ~(TRIDOI_FAST+TRADOI_VSLOW); // clear fields
  ctsStatusReg |= (rate & 0xF0); // update fields
}

/***************************************************************************//**
 * @brief   Measure the change in capacitance of the Sensor
 * 
 *          This function measures the change in capacitance of each element
 *          within a sensor and updates the baseline tracking in the event that
 *          no change exceeds the detection threshold.
 *          The order of the elements within the Sensor structure is arbitrary 
 *          but must be consistent between the application and configuration. 
 *          The first element in the array (deltaCnt) corresponds to the first 
 *          element within the Sensor structure.
 * @param   groupOfElements Pointer to Sensor structure to be measured
 * @param   deltaCnt Address to where the measurements are to be written
 * @return  none
 ******************************************************************************/
void TI_CAPT_Custom(const struct Sensor* groupOfElements, uint16_t * deltaCnt)
{ 
    uint8_t j;
    uint16_t tempCnt;
    ctsStatusReg &= ~ EVNT;
        
    // This section calculates the delta counts*************************************
    //******************************************************************************
    TI_CAPT_Raw(groupOfElements, &deltaCnt[0]); // measure group of sensors
  
    for (j = 0; j < (groupOfElements->numElements); j++)
    {  
        tempCnt = deltaCnt[j];
        if(((ctsStatusReg & DOI_MASK) && (groupOfElements->halDefinition & RO_MASK))
        || 
         ((!(ctsStatusReg & DOI_MASK)) && (!(groupOfElements->halDefinition & RO_MASK))))
        { 
            // RO method, interested in an increase in capacitance
            if(baseCnt[j+groupOfElements->baseOffset] < deltaCnt[j])            
            {
                // If capacitance decreases, then measCnt is greater than base
                // , set delta to zero
                deltaCnt[j] = 0;
                // Limit the change in the opposite direction to the threshold
                if(((groupOfElements->arrayPtr[j])->threshold)
                &&
                (baseCnt[j+groupOfElements->baseOffset]+(groupOfElements->arrayPtr[j])->threshold < tempCnt))
                {
                    tempCnt = baseCnt[j+groupOfElements->baseOffset]+(groupOfElements->arrayPtr[j])->threshold;
                }
            }
            else
            {
                // change occuring in our DOI, save result
                deltaCnt[j] = baseCnt[j+groupOfElements->baseOffset]-deltaCnt[j];
            }
        }
        if(((!(ctsStatusReg & DOI_MASK)) && (groupOfElements->halDefinition & RO_MASK))
           ||
             ((ctsStatusReg & DOI_MASK) && (!(groupOfElements->halDefinition & RO_MASK))))
        { 
            // RO method: interested in a decrease in capactiance
            //  measCnt is greater than baseCnt
            if(baseCnt[j+groupOfElements->baseOffset] > deltaCnt[j])            
            {
                // If capacitance increases, set delta to zero
                deltaCnt[j] = 0;
                // Limit the change in the opposite direction to the threshold
                if(((groupOfElements->arrayPtr[j])->threshold)
                &&
                (baseCnt[j+groupOfElements->baseOffset] > tempCnt+(groupOfElements->arrayPtr[j])->threshold))
                {
                    tempCnt = baseCnt[j+groupOfElements->baseOffset]-(groupOfElements->arrayPtr[j])->threshold;
                }
            }
            else       
            {
                // change occuring in our DOI
                deltaCnt[j] = deltaCnt[j] - baseCnt[j+groupOfElements->baseOffset];
            }         
        }
            
        // This section updates the baseline capacitance****************************
        //**************************************************************************  
        if (deltaCnt[j]==0)
        { // if delta counts is 0, then the change in capacitance was opposite the
          // direction of interest.  The baseCnt[i] is updated with the saved 
          // measCnt value for the current index value 'i'.
          switch ((ctsStatusReg & TRADOI_VSLOW))
          {
            case TRADOI_FAST://Fast
                    tempCnt = tempCnt/2;
                    baseCnt[j+groupOfElements->baseOffset] = (baseCnt[j+groupOfElements->baseOffset]/2);
                    break;
            case TRADOI_MED://Medium
                    tempCnt = tempCnt/4;
                    baseCnt[j+groupOfElements->baseOffset] = 3*(baseCnt[j+groupOfElements->baseOffset]/4);
                    break;
            case TRADOI_SLOW://slow
                  tempCnt = tempCnt/64;
                  baseCnt[j+groupOfElements->baseOffset] = 63*(baseCnt[j+groupOfElements->baseOffset]/64);
                    break;
            case TRADOI_VSLOW://very slow
                  tempCnt = tempCnt/128;
                  baseCnt[j+groupOfElements->baseOffset] = 127*(baseCnt[j+groupOfElements->baseOffset]/128);
              break;
          }
          // set X, Y & Z, then perform calculation for baseline tracking:
          // Base_Capacitance = X*(Measured_Capacitance/Z) + Y*(Base_Capacitance/Z)
          baseCnt[j+groupOfElements->baseOffset] = (tempCnt)+(baseCnt[j+groupOfElements->baseOffset]);
        }
            // delta counts are either 0, less than threshold, or greater than threshold
            // never negative
        else if(deltaCnt[j]<(groupOfElements->arrayPtr[j])->threshold && !(ctsStatusReg & PAST_EVNT))
        {    //if delta counts is positive but less than threshold,
          switch ((ctsStatusReg & TRIDOI_FAST))
          {
            case TRIDOI_VSLOW://very slow
              if(deltaCnt[j] > 15)
              {
                  if(tempCnt < baseCnt[j+groupOfElements->baseOffset])
                  {
                     baseCnt[j+groupOfElements->baseOffset] = baseCnt[j+groupOfElements->baseOffset] - 1;               
                  }
                  else
                  {
                     baseCnt[j+groupOfElements->baseOffset] = baseCnt[j+groupOfElements->baseOffset] + 1;               
                  }
              }
              tempCnt = 0;
              break;
            case TRIDOI_SLOW://slow
              if(tempCnt < baseCnt[j+groupOfElements->baseOffset])
              {
                 baseCnt[j+groupOfElements->baseOffset] = baseCnt[j+groupOfElements->baseOffset] - 1;               
              }
              else
              {
                 baseCnt[j+groupOfElements->baseOffset] = baseCnt[j+groupOfElements->baseOffset] + 1;               
              }
              tempCnt = 0;
              break;
            case TRIDOI_MED://medium
                tempCnt = tempCnt/4;
                baseCnt[j+groupOfElements->baseOffset] = 3*(baseCnt[j+groupOfElements->baseOffset]/4);
                break;
            case TRIDOI_FAST://fast
                tempCnt = tempCnt/2;
                baseCnt[j+groupOfElements->baseOffset] = (baseCnt[j+groupOfElements->baseOffset]/2);
                break;
          }
          // set X, Y & Z, then perform calculation for baseline tracking:
          // Base_Capacitance = X*(Measured_Capacitance/Z) + Y*(Base_Capacitance/Z)
          baseCnt[j+groupOfElements->baseOffset] = (tempCnt)+(baseCnt[j+groupOfElements->baseOffset]);
        }
        //if delta counts above the threshold, event has occurred
        else if(deltaCnt[j]>=(groupOfElements->arrayPtr[j])->threshold)
        {
          ctsStatusReg |= EVNT;
          ctsStatusReg |= PAST_EVNT;
        }
    }// end of for-loop
    if(!(ctsStatusReg & EVNT))
    {
      ctsStatusReg &= ~PAST_EVNT;
    }
}

/***************************************************************************//**
 * @brief   Determine if a button is being pressed
 * @param   groupOfElements Pointer to button to be scanned
 * @return  result Indication if button is (1) or is not (0) being pressed
 ******************************************************************************/
uint8_t TI_CAPT_Button(const struct Sensor * groupOfElements)
{
    uint8_t result = 0;
    
    #ifndef RAM_FOR_FLASH
    uint16_t *measCnt;
    measCnt = (uint16_t *)malloc(groupOfElements->numElements * sizeof(uint16_t));
    if(measCnt ==0)
    {
        while(1);
    }
    #endif
    
    TI_CAPT_Custom(groupOfElements, measCnt);
    #ifndef RAM_FOR_FLASH
    free(measCnt);
    #endif
    if(ctsStatusReg & EVNT)
    {
        result = 1;
    }    
    return result;
}

/***************************************************************************//**
 * @brief   Determine which button if any is being pressed
 * @param   groupOfElements Pointer to buttons to be scanned
 * @return  result pointer to element (button) being pressed or 0 none
 ******************************************************************************/
const struct Element *TI_CAPT_Buttons(const struct Sensor *groupOfElements)
{
    uint8_t index;
    #ifndef RAM_FOR_FLASH
    uint16_t *measCnt;
    measCnt = (uint16_t *)malloc(groupOfElements->numElements * sizeof(uint16_t));
    if(measCnt ==0)
    {
        while(1);
    }
    #endif
    TI_CAPT_Custom(groupOfElements, measCnt);
    
    if(ctsStatusReg & EVNT)
    {
        index = Dominant_Element(groupOfElements, measCnt);
        //ctsStatusReg &= ~EVNT;
        index++;
    }
    else 
    {
        index = 0;
    }
    #ifndef RAM_FOR_FLASH
    free(measCnt);
    #endif
    if(index)
    {
      return groupOfElements->arrayPtr[index-1];
    }
    return 0;
}

#ifdef SLIDER
/***************************************************************************//**
 * @brief   Determine the position on a slider
 * @param   groupOfElements Pointer to slider
 * @return  result position on slider or illegal value if no touch
 ******************************************************************************/
uint16_t TI_CAPT_Slider(const struct Sensor* groupOfElements)
{
    uint8_t index;
    int16_t position;
    // allocate memory for measurement
    #ifndef RAM_FOR_FLASH
    uint16_t *measCnt;
    measCnt = (uint16_t *)malloc(groupOfElements->numElements * sizeof(uint16_t));
    if(measCnt ==0)
    {
        while(1);
    }
    #endif
    position = ILLEGAL_SLIDER_WHEEL_POSITION;
    //make measurement
    TI_CAPT_Custom(groupOfElements, measCnt);
    
    // Use EVNT flag to determine if slider was touched.
    // The EVNT flag is a global variable and managed within the TI_CAPT_Custom function.
    if(ctsStatusReg & EVNT)
    {
        index = Dominant_Element(groupOfElements, &measCnt[0]);
        // The index represents the element within the array with the highest return.
        if(index == 0)
        {
          // Special case of 1st element in slider, add 1st, last, and 2nd
          position = measCnt[0] + measCnt[1];
        }
        else if(index == (groupOfElements->numElements -1))
        {
          // Special case of Last element in slider, add last, 1st, and 2nd to last
          position = measCnt[groupOfElements->numElements -1] + measCnt[groupOfElements->numElements -2];
        }
        else
        {
          position = measCnt[index] + measCnt[index+1] + measCnt[index-1];
        } 
        // Determine if sensor threshold criteria is met
        if(position > groupOfElements->sensorThreshold)
        {
            // calculate position
    	    position = index*(groupOfElements->points/groupOfElements->numElements);
            position += (groupOfElements->points/groupOfElements->numElements)/2;
            if(index == 0)
            {
              // Special case of 1st element in slider, which only has one 
              // neighbor, measCnt[1]. measCnt is limited to maxResponse 
              // within dominantElement function
              if(measCnt[1])
              {
                  position += (measCnt[1]*(groupOfElements->points/groupOfElements->numElements))/100;
              }
              else
              {
                  position = (measCnt[0]*(groupOfElements->points/groupOfElements->numElements)/2)/100;
              }
            }
            else if(index == (groupOfElements->numElements -1))
            {
              // Special case of Last element in slider, which only has one 
              // neighbor, measCnt[x-1] or measCnt[numElements-1]
              if(measCnt[index-1])
              {
                  position -= (measCnt[index-1]*(groupOfElements->points/groupOfElements->numElements))/100;
              }
              else
              {
                  position = groupOfElements->points;
                  position -= (measCnt[index]*(groupOfElements->points/groupOfElements->numElements)/2)/100;
              }
            }
            else
            {
                  position += (measCnt[index+1]*(groupOfElements->points/groupOfElements->numElements))/100;
                  position -= (measCnt[index-1]*(groupOfElements->points/groupOfElements->numElements))/100;
            }  
            if((position > groupOfElements->points) || (position < 0))
            {
                  position = ILLEGAL_SLIDER_WHEEL_POSITION;
            }     
        }
        else
        {
            position = ILLEGAL_SLIDER_WHEEL_POSITION;
        }
    }
    #ifndef RAM_FOR_FLASH
    free(measCnt);
    #endif
    return position;
}
#endif

#ifdef WHEEL
/***************************************************************************//**
 * @brief   Determine the position on a wheel
 * @param   groupOfElements Pointer to wheel
 * @return  result position on wheel or illegal value if no touch
 ******************************************************************************/
uint16_t TI_CAPT_Wheel(const struct Sensor* groupOfElements)
{
    uint8_t index;
    int16_t position;
    // allocate memory for measurement
    #ifndef RAM_FOR_FLASH
    uint16_t *measCnt;
    measCnt = (uint16_t *)malloc(groupOfElements->numElements * sizeof(uint16_t));
    if(measCnt ==0)
    {
        while(1);
    }
    #endif
    position = ILLEGAL_SLIDER_WHEEL_POSITION;
    //make measurement
    TI_CAPT_Custom(groupOfElements, measCnt);
    // Translate the EVNT flag from an element level EVNT to a sensor level EVNT.
    // The sensor must read at least 75% cumulative response before indicating a 
    // touch.
    if(ctsStatusReg & EVNT)
    {
        index = Dominant_Element(groupOfElements, &measCnt[0]);
        // The index represents the element within the array with the highest return.
        // 
        if(index == 0)
        {
          // Special case of 1st element in slider, add 1st, last, and 2nd
          position = measCnt[0] + measCnt[groupOfElements->numElements -1] + measCnt[1];
        }
        else if(index == (groupOfElements->numElements -1))
        {
          // Special case of Last element in slider, add last, 1st, and 2nd to last
          position = measCnt[index] + measCnt[0] + measCnt[index-1];
        }
        else
        {
          position = measCnt[index] + measCnt[index+1] + measCnt[index-1];
        } 
        if(position > groupOfElements->sensorThreshold)
        {
            //index = Dominant_Element(groupOfElements, &measCnt[0]);
            // The index represents the element within the array with the highest return.
            // 
            position = index*(groupOfElements->points/groupOfElements->numElements);
            position += (groupOfElements->points/groupOfElements->numElements)/2;
            if(index == 0)
            {
              // Special case of 1st element in slider, which only has one neighbor, measCnt[1]
              // measCnt is limited to maxResponse within dominantElement function
              position += (measCnt[1]*(groupOfElements->points/groupOfElements->numElements))/100;
              position -= (measCnt[groupOfElements->numElements -1]*(groupOfElements->points/groupOfElements->numElements))/100;
              if(position < 0)
              {
                position = position + (int16_t)groupOfElements->points;
              }
            }
            else if(index == (groupOfElements->numElements -1))
            {
              // Special case of Last element in slider, which only has one neighbor, measCnt[x-1] or measCnt[numElements-1]
              // measCnt is limited to maxResponse within dominantElement function
              position += (measCnt[0]*(groupOfElements->points/groupOfElements->numElements))/100;
              position -= (measCnt[index-1]*(groupOfElements->points/groupOfElements->numElements))/100;
              if(position > (groupOfElements->points -1))
              {
                position = position - (int16_t)groupOfElements->points;
              }
            }
            else
            {
              position += (measCnt[index+1]*(groupOfElements->points/groupOfElements->numElements))/100;
              position -= (measCnt[index-1]*(groupOfElements->points/groupOfElements->numElements))/100;
            } 
            if((position > groupOfElements->points) || position < 0)
            {
                  position = ILLEGAL_SLIDER_WHEEL_POSITION;
            }     
        }
        else 
        {
            position = ILLEGAL_SLIDER_WHEEL_POSITION;
        }
    }
    #ifndef RAM_FOR_FLASH
    free(measCnt);
    #endif
    return position;
}
#endif

/***************************************************************************//**
 * @}
 ******************************************************************************/

/***************************************************************************//**
 * @defgroup CTS_support
 * @ingroup CTS_API
 ******************************************************************************/
  
/***************************************************************************//**
 * @ingroup CTS_support
 * @brief   Determine which element within a sensor has the largest response
 * 
 *          This function compares and normalizes the change in capacitance to
 *          determine which element has the dominant response.  The deltaCnt
 *          values for each element that exceed the threshold are also 
 *          converted from a 'raw' measurement to a percentage of the maximum 
 *          response.
 * @param   groupOfElements Pointer to buttons to be scanned
 * @param   deltaCnt Address to where the measurements are to be written
 * @return  result index to the element which is dominant
 ******************************************************************************/
uint8_t Dominant_Element(const struct Sensor* groupOfElements, uint16_t* deltaCnt)
{
    uint8_t i;
    uint16_t percentDelta=0; 
    uint8_t dominantElement=0;
    for(i=0;i<groupOfElements->numElements;i++)
    {  
        if(deltaCnt[i]>=(groupOfElements->arrayPtr[i])->threshold)
        {
            if(deltaCnt[i] > ((groupOfElements->arrayPtr[i])->maxResponse))
            {
                deltaCnt[i] = (groupOfElements->arrayPtr[i])->maxResponse;
                // limit response to the maximum
            }
            // (maxResponse - threshold) cannot exceed 655
            // 100*(delta - threshold) / (maxResponse - threshold)
            deltaCnt[i] = (100*(deltaCnt[i]-(groupOfElements->arrayPtr[i])->threshold))/((groupOfElements->arrayPtr[i])->maxResponse - (groupOfElements->arrayPtr[i])->threshold);
            if(deltaCnt[i] > percentDelta)
            {
                //update percentDelta
                percentDelta = deltaCnt[i];
                dominantElement = i;
            }
        }
        else
        {
            deltaCnt[i] = 0;
        }
    } // end for loop    
    return dominantElement;
}
#endif