Пример #1
0
/***************************************************************************//**
 * @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;
}
Пример #2
0
//*****************************************************************************
//
//! Determine which element in a multi-element sensor is being pressed, if any.
//!
//! \param psSensor Pointer to sensor containing elements to be scanned.
//!
//! This function takes a capacitive measurement of all elements in \e
//! psSensor, and checks to see if any element has exceeded the threshold for a
//! touch event. If so, it will will return a pointer to the most active
//! element, normalized by the \e ui32MaxResponse for each element. This
//! function can be used with multi-element sensors to create an array of
//! mutually exclusive buttons.
//!
//! Please note that this function will also update the baseline capacitance
//! for all elements in the sensor psSensor.
//!
//! \return Returns a pointer to the element (button) being pressed or 0 if no
//! element was pressed.
//
//*****************************************************************************
const tCapTouchElement *
TI_CAPT_Buttons(const tSensor *psSensor)
{
    uint8_t ui8Index;

    //
    // Find the delta counts of all elements in the given sensor.
    //
    TI_CAPT_Custom(psSensor, g_pui32MeasCount);

    //
    // If at least one element was pressed, find the dominant element
    // (normalized by maximum response), and return a pointer to that element
    // back to the caller.
    //
    if(g_ui32CtsStatusReg & EVNT)
    {
        ui8Index = Dominant_Element(psSensor, g_pui32MeasCount);

        return(psSensor->psElement[ui8Index]);
    }
    else
    {
        //
        // If there were no touch events at all, return a zero.
        //
        return(0);
    }
}
Пример #3
0
//*****************************************************************************
//
//! Determine if any element in the given sensor is being pressed.
//!
//! \param psSensor pointer to the sensor structure whose elements are to be
//! scanned for button presses.
//!
//! This function takes measrements of all elements in \e psSensor and checks
//! to see if any element has exceeded its threshold for a touch event. This
//! function can be used with single-element sensors to create a capacitive
//! "button". The return value is a simple 1 or 0 indication of whether the
//! button is currently being pressed.
//!
//! Please note that this function will also update the baseline capacitance
//! for all elements in the sensor psSensor.
//!
//! \return  Indication if button is pressed (1) or is not being pressed (0)
//
//*****************************************************************************
uint8_t
TI_CAPT_Button(const tSensor *psSensor)
{
    uint8_t ui8Result;

    //
    // Start with the assumption that no button was pressed.
    //
    ui8Result = 0;

    //
    // Perform a quick measurement of the delta counts on the chosen sensor.
    //
    TI_CAPT_Custom(psSensor, g_pui32MeasCount);

    //
    // Check to see if any threshold-crossing events were recorded.
    //
    if(g_ui32CtsStatusReg & EVNT)
    {
        //
        // If so, the button is being pressed. Return a 1. Otherwise return a
        // zero.
        //
        ui8Result = 1;
    }

    return ui8Result;
}
Пример #4
0
// Main Function
void main(void)
{ 

  // Initialize System Clocks
  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer
  
  //Clock Setting
  CSCTL1 &= ~(DCORSEL_7);                 // Clear DCO frequency select bits first
  CSCTL1 |= DCORSEL_3;                    // Set DCO = 8MHz, max in G6021
  CSCTL2 = FLLD_0 + 243;                  // DCODIV = 8MHz
  CSCTL3 |= SELREF__REFOCLK;              // Set REFO as FLL reference source
  CSCTL4 = SELMS__DCOCLKDIV | SELREF__REFOCLK; // set default REFO(~32768Hz) as ACLK source, ACLK = 32768Hz
  CSCTL5 |= DIVM_0 | DIVS_0;              // SMCLK = MCLK = DCODIV/1 = 8MHz

  // Initializing GPIO
  P8DIR |= BIT1;                         //Set the pin controlling the center LED P8.1  as output pin
  PM5CTL0 &= ~LOCKLPM5;


  // Initialize Baseline measurement
  TI_CAPT_Init_Baseline(&one_button);
  
  //TI_CAPT_Init_Baseline(&one_button);

   //Update baseline measurement (Average 100 measurements)
  
  TI_CAPT_Update_Baseline(&one_button,100);

  // Main loop starts here
  while (1)
  {
  	
  	#ifdef ELEMENT_CHARACTERIZATION_MODE
	// Get the raw delta counts for element characterization 
	TI_CAPT_Custom(&one_button,&dCnt);
	__no_operation(); 					// Set breakpoint here	
	#endif
	  	
	#ifndef ELEMENT_CHARACTERIZATION_MODE	  	
	// Check if the middle element sensor has been triggered. The API call
	// compares the value from the sensor against the threshold to determine
	// trigger condition

	if(TI_CAPT_Button(&one_button))
	{
		// Do something
		P8OUT |= BIT1;                            // Turn on center LED
	}
	else
	{
		P8OUT &= ~BIT1;                           // Turn off center LED
	}
	
    // Put the MSP430 into LPM3 for a certain DELAY period
    sleep(DELAY);
    #endif
  }
} // End Main
Пример #5
0
// Main Function
void main(void)
{ 

  // Initialize System Clocks
  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer
  BCSCTL1 = CALBC1_1MHZ;                // Set DCO to 1, 8, 12 or 16MHz
  DCOCTL = CALDCO_1MHZ;
  BCSCTL2 |= DIVS_2;                    // divide SMCLK by 4 for 250khz      
  BCSCTL3 |= LFXT1S_2;                  // LFXT1 = VLO
  
  P1OUT = 0x00;							// Clear Port 1 bits
  P1DIR |= BIT0;						// Set P1.0 as output pin

  P2SEL &= ~(BIT6 + BIT7);				// Configure XIN (P2.6) and XOUT (P2.7) to GPIO
  P2OUT = 0x00;							// Drive all Port 2 pins low
  P2DIR = 0xFF;							// Configure all Port 2 pins outputs

  // Initialize Baseline measurement
  TI_CAPT_Init_Baseline(&one_button);
  
  // Update baseline measurement (Average 5 measurements)
  TI_CAPT_Update_Baseline(&one_button,5);  
  
  // Main loop starts here
  while (1)
  {
  	
  	#ifdef ELEMENT_CHARACTERIZATION_MODE
	// Get the raw delta counts for element characterization 
	TI_CAPT_Custom(&one_button,&dCnt);
	__no_operation(); 					// Set breakpoint here	
	#endif
	  	
	#ifndef ELEMENT_CHARACTERIZATION_MODE	  	
	// Check if the middle element sensor has been triggered. The API call
	// compares the value from the sensor against the threshold to determine
	// trigger condition  	
	if(TI_CAPT_Button(&one_button))
	{
		// Do something
		P1OUT |= BIT0;                            // Turn on center LED   
	}
	else
	{
		P1OUT &= ~BIT0;                           // Turn off center LED 
	}
	
    // Put the MSP430 into LPM3 for a certain DELAY period
    sleep(DELAY);		
    #endif

  }
} // End Main
Пример #6
0
// Main Function
void main(void)
{ 

  // Initialize System Clocks
  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer
  
  //Clock Setting
  CSCTL0_H = 0xA5;                          // Unlock CS
  CSCTL1 = DCORSEL + DCOFSEL_5;             // Set DCO = 20MHz, use this clk when fRO
  CSCTL2 = SELA__VLOCLK + SELS_3 + SELM_3;  // set SMCLK = MCLK = DCO  LFXT1 = VLO
  CSCTL0_H = 0;                             // Lock CS registers

  P4DIR |= BIT2;						// Set the pin controlling the center LED P4.2  as output pin

  // Initialize Baseline measurement
  TI_CAPT_Init_Baseline(&one_button);
  
  // Update baseline measurement (Average 5 measurements)
  TI_CAPT_Update_Baseline(&one_button,5);  
  
  // Main loop starts here
  while (1)
  {
  	
  	#ifdef ELEMENT_CHARACTERIZATION_MODE
	// Get the raw delta counts for element characterization 
	TI_CAPT_Custom(&one_button,&dCnt);
	__no_operation(); 					// Set breakpoint here	
	#endif
	  	
	#ifndef ELEMENT_CHARACTERIZATION_MODE	  	
	// Check if the middle element sensor has been triggered. The API call
	// compares the value from the sensor against the threshold to determine
	// trigger condition

	if(TI_CAPT_Button(&one_button))
	{
		// Do something
		P4OUT |= BIT2;                            // Turn on center LED
	}
	else
	{
		P4OUT &= ~BIT2;                           // Turn off center LED
	}
	
    // Put the MSP430 into LPM3 for a certain DELAY period
    sleep(DELAY);
    #endif
  }
} // End Main
/* ----------------CapTouchIdleMode-----------------------------------------
 * Device stays in LPM3 'sleep' mode, only Proximity Sensor is used to detect
 * any movement triggering device wake up
 * ------------------------------------------------------------------------*/
void CapTouchIdleMode(void)
{
  /* Send status via UART: 'sleep' = [0xDE, 0xAD] */
  SendByte(SLEEP_MODE_UART_CODE);
  SendByte(SLEEP_MODE_UART_CODE2);

	/* Set DCO to 1MHz */
	/* Set SMCLK to 8MHz / 8 = 1MHz */
//	BCSCTL1 = CALBC1_8MHZ;
//	DCOCTL = CALDCO_8MHZ;
//	BCSCTL2 |= DIVS_3;

	/* Set SMCLK to 1MHz / 4 = 250kHz */
//	BCSCTL1 = CALBC1_1MHZ;
//	DCOCTL = CALDCO_1MHZ;
//	BCSCTL2 |= DIVS_2;

	/* Set SMCLK to 1.5MHz */
	BCSCTL1 = CALBC1_12MHZ;
	DCOCTL = CALDCO_12MHZ;
//	BCSCTL2 |= DIVS_3;


  P1OUT |= BIT0;                            // Turn on center LED
  deltaCnts[0] = 0;

  /* Sleeping in LPM3 with ACLK/100 = 12Khz/100 = 120Hz wake up interval */
  /* Measure proximity sensor count upon wake up */
  /* Wake up if proximity deltaCnts > THRESHOLD */
  do
  {
    TACCR0 = 100;
    TACTL = TASSEL_1 + MC_1;
    TACCTL0 |= CCIE;
    __bis_SR_register(LPM3_bits+GIE);
    TACCTL0 &= ~CCIE;
    TI_CAPT_Custom(&proximity_sensor,deltaCnts);
  }
  while (deltaCnts[0] <= PROXIMITY_THRESHOLD);

  P1OUT &= ~BIT0;                           // Turn off center LED
}
Пример #8
0
/***************************************************************************//**
 * @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;
}
Пример #9
0
// Main Function
void main(void)
{ 
  
  uint8_t last = 0;
  
  WDTCTL = WDTPW + WDTHOLD;             // Stop watchdog timer
  BCSCTL1 = CALBC1_16MHZ;               // Set DCO to 1, 8, 12 or 16MHz
  DCOCTL = CALDCO_16MHZ;
  BCSCTL1 |= DIVA_0;                    // ACLK/1 [ACLK/(0:1,1:2,2:4,3:8)]
  //BCSCTL2 |= DIVS_3;                  // SMCLK/8 [SMCLK/(0:1,1:2,2:4,3:8)]
  BCSCTL3 |= LFXT1S_2;                  // LFXT1 = VLO Clock Source
  
  P1OUT |= BIT0;				// P1.0 out
  P1DIR |= BIT0;				// P1.0 high
  
  P2DIR |= BIT0 | BIT1 | BIT4 | BIT5;			// Configure  Port 2 pins outputs

  // Initialize Baseline measurement
  TI_CAPT_Init_Baseline(&button_bar);
  
  // Update baseline measurement (Average 5 measurements)
  TI_CAPT_Update_Baseline(&button_bar,5);  
  
  SPISetup();                         // Initialize SPI Display
  //drawBitmap(blackbird_96_64, 96, 8, 0, 0);    
  
  clear();
  //setcharmode(1); //largechars
  //writeString(2,1,"Press button!");
  
  // Main loop starts here
  while (1)
  {
  	
  	#ifdef ELEMENT_CHARACTERIZATION_MODE
	// Get the raw delta counts for element characterization 
	TI_CAPT_Custom(&button_bar,wheelCnt);
	__no_operation(); 					// Set breakpoint here	
	#endif
	
	
	#ifndef ELEMENT_CHARACTERIZATION_MODE
	// Return the pointer to the element which has been touched
	keyPressed = (struct Element *)TI_CAPT_Buttons(&button_bar);
	
	// If a button has been touched, then take some action
	if(keyPressed)
	{
		// Up Element
		if(keyPressed == &a_element)
		{
			P1OUT |= BIT0;				// Turn on center LED
                        if (last != 2) {                        
                            clear();
                            last = 2;
                            drawBitmap(big_1, 32, 6, 32, 1);
                            //writeString(4,3,"A Pressed");
                        }
		}
		if(keyPressed == &b_element)
		{
			P1OUT |= BIT0;				// Turn on center LED
                        if (last != 3) {                        
                            clear();
                            last = 3;
                            drawBitmap(big_2, 32, 6, 32, 1);
                            //writeString(4,3,"B Pressed");
                        }
		}
		if(keyPressed == &c_element)
		{
			P1OUT |= BIT0;				// Turn on center LED
                        if (last != 1) {                        
                            clear();
                            last = 1;
                            drawBitmap(big_3, 32, 6, 32, 1);
                            //writeString(4,3,"C Pressed");
                        }
		}
		if(keyPressed == &d_element)
		{
			P1OUT |= BIT0;				// Turn on center LED
                        if (last != 4) {                        
                            clear();
                            last = 4;
                            drawBitmap(big_4, 32, 6, 32, 1);
                            //writeString(4,3,"D Pressed");
                        }
		}		
	  }
	  else
	  {
	      P1OUT &= ~(BIT0);				// Turn off center LED
              if (last != 0) 
              {
                drawBitmap(blackbird_96_64, 96, 8, 0, 0);  
                //writeString(4,4,"Press a button");
                last = 0;
              }
	  }      
        
    // Put the MSP430 into LPM3 for a certain DELAY period
    sleep(DELAY);
    #endif

  }
} // End Main
Пример #10
0
/***************************************************************************//**
 * @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;
}
Пример #11
0
/***************************************************************************//**
 * @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;
}
Пример #12
0
//*****************************************************************************
//
//! Detect touch events on a wheel element, and return the position of any
//! touch event found in units of points.
//!
//! \param psSensor Pointer to the wheel element to be measured.
//!
//! This function performs a capacitive measurement on the given sensor \e
//! psSensor, and interprets the results assuming that this sensor represents a
//! physical wheel. Its return value is a numerical position along the surface
//! of the wheel. A position of zero represents a touch on the wheel centered
//! at the point where the element of index zero and the last element in the
//! array physically touch. Position values increase around the circumference
//! of the wheel in the same direction as increasing element indices in the \e
//! psSensor structure.
//!
//! Please note that this function will also update the baseline capacitance
//! for all elements in the sensor \e psSensor.
//!
//! \return  Returns the calculate position of the touch event on the wheel or
//! an illegal value \b ILLEGAL_SLIDER_WHEEL_POSITION if no touch was detected.
//
//*****************************************************************************
uint32_t
TI_CAPT_Wheel(const tSensor* psSensor)
{
    uint8_t ui8NumElements, ui8Points, ui8PointsPerElement;
    uint8_t ui8Index;
    uint32_t ui32SensorThreshold, ui32WheelPosition;
    uint32_t ui32ThresholdCheck;

    //
    // Gather important sensor-level information
    //
    ui32SensorThreshold = psSensor->ui32SensorThreshold;
    ui8NumElements = psSensor->ui8NumElements;
    ui8Points = psSensor->ui8Points;
    ui8PointsPerElement = ui8Points / ui8NumElements;

    //
    // Take a measurement of delta counts, and store it in our global
    // measurement array.
    //
    TI_CAPT_Custom(psSensor, g_pui32MeasCount);

    //
    // Check the global EVNT flag to see if any elements in this sensor are
    // active. If not, we can skip the calculations and simply return an
    // illegal position.
    //
    if(g_ui32CtsStatusReg & EVNT)
    {
        //
        // If we did have a touch event, normalize the responses and find the
        // index of the dominant element.
        //
        ui8Index = Dominant_Element(psSensor, &g_pui32MeasCount[0]);

        //
        // Check to see if the normalized responses of the dominant element and
        // the adjacent elements are collectively high enough to cross the
        // overall sensor threshold. If so, we can conclude that the touch
        // event is somewhere within the intended track of the physical wheel,
        // and we can go ahead and calculate the position.  Make sure to handle
        // the first and last elements carefully, as their neighbors wrap
        // around the array boundary.
        //
        if(ui8Index == 0)
        {
            ui32ThresholdCheck = (g_pui32MeasCount[ui8Index] +
                                  g_pui32MeasCount[ui8Index + 1] +
                                  g_pui32MeasCount[ui8NumElements - 1]);
        }
        else if(ui8Index == (ui8NumElements - 1))
        {
            ui32ThresholdCheck = (g_pui32MeasCount[ui8Index] +
                                  g_pui32MeasCount[ui8Index - 1] +
                                  g_pui32MeasCount[0]);
        }
        else
        {
            ui32ThresholdCheck = (g_pui32MeasCount[ui8Index] +
                                  g_pui32MeasCount[ui8Index + 1] +
                                  g_pui32MeasCount[ui8Index - 1]);
        }

        //
        // If we didn't pass our threshold check, we probably have a touch
        // event close to the sensor, but not actually in the desired region of
        // the physical wheel. This means we should stop our calculation here
        // and return an illegal position value.
        //
        if(ui32ThresholdCheck < ui32SensorThreshold)
        {
            return ILLEGAL_SLIDER_WHEEL_POSITION;
        }

        //
        // If we passed the check, it's time to calculate the position (in
        // points) of the touch.  We will start with the assumption that the
        // touch is in the exact center of the dominant element
        //
        ui32WheelPosition = ((ui8Index * ui8PointsPerElement) +
                             (ui8PointsPerElement / 2));

        //
        // Then we will improve our calculation of the touch position by
        // factoring in the measurements from the two adjacent elements. The
        // first and last sensors in the wheel are special cases, as each of
        // them only has one adjacent element.
        //
        if(ui8Index == 0)
        {
            //
            // Special case for the first element in the array, which requires
            // wrapping of the index.
            //
            ui32WheelPosition += ((g_pui32MeasCount[ui8Index + 1] *
                                   ui8PointsPerElement) / 100);

            ui32WheelPosition -= ((g_pui32MeasCount[ui8NumElements - 1] *
                                   ui8PointsPerElement) / 100);
        }
        else if(ui8Index == (ui8NumElements - 1))
        {
            //
            // Special case for the last element in the array, which requires
            // wrapping of the index.
            //
            ui32WheelPosition += ((g_pui32MeasCount[0] *
                                   ui8PointsPerElement) / 100);

            ui32WheelPosition -= ((g_pui32MeasCount[ui8Index - 1] *
                                   ui8PointsPerElement) / 100);
        }
        else
        {
            //
            // No wrapping necessary, so just push the position based on the
            // measurements of the adjacent elements
            //
            ui32WheelPosition += ((g_pui32MeasCount[ui8Index + 1] *
                                   ui8PointsPerElement) / 100);

            ui32WheelPosition -= ((g_pui32MeasCount[ui8Index - 1] *
                                   ui8PointsPerElement) / 100);
        }

        //
        // Return the adjusted position back to the caller.
        //
        return ui32WheelPosition;

    }
    else
    {
        //
        // We didn't register any touch events at all, so return an illegal
        // wheel position
        //
        return ILLEGAL_SLIDER_WHEEL_POSITION;
    }
}