/*************************************************
* EEL3111 Student Project - Force Sensor Group
* Code by: Michael Toth
* Questions: totm0001@unf.edu
*************************************************/

#include "msp430x44x.h"
#include "lcd.h"
#include "math.h"

#define Average 4  // This value controls the number of samples
                   // to be taken before an average is computed
                   // and the LCD is updated.
#define Vref 3.3   // Don't change this unless you know what you are doing

volatile unsigned int x=1;
long int ADC0;
float ADC0Averaged;
float ADC0temp;
float Voltage;
float Converted;
unsigned int hundreds, tens, ones, tenths;


/************************************
* Function Prototypes
************************************/
void clock_config(void);
void adc12_config(void);
//void opamp_enable(int);
void update_lcd(void);
float convert_value(float);
void extract_digits(float);

/************************************
* Main Loop
************************************/
void main(void)
{
  clock_config();   // Configure clock
  adc12_config();   // Configure ADC12
 // opamp_enable(1);  // 1=enabled 0=disabled
  setupLCD();       // Called from lcd.c, performs LCD setup
  lcd_all(0);       // clear the LCD

  // Enable interrupts and go to sleep forever
  _EINT();
  
  while(1){
    _NOP();   // loop forever but still servicing interrupts    
  }
}

/************************************
* Clock Configuration Subroutine
************************************/
void clock_config(void){  
  WDTCTL = WDTPW + WDTHOLD;         // Stop WDT
  FLL_CTL0 |= XCAP10PF;             // Configure load caps
  BTCTL = BT_ADLY_250;              // 250ms Interrupt
  IE2 |= BTIE;                      // Enable BT interrupt
}

/************************************
* ADC12 Configuration Subroutine
************************************/
void adc12_config(void){
  ADC12IE |= 0x01;                      // Enable ADCMEM0 interrupt
  ADC12CTL1 = ADC12SSEL_2 | SHP;        // ADCCLK = mCLK, pulse mode
  ADC12MCTL0 = SREF_0 | INCH_0;         // Vr+=AVcc and Vr-=AVss 
  // warm-up the ADC
  ADC12CTL0 = REFON | ADC12ON;          // turn on ref and ADC
  ADC12CTL0 |= ENC;                     // enable conversions
}

/************************************
* Opamp Enable Subroutine:
* The project board includes a place for
* a surface mounted opamp. The opamp has
* a pin that must be set high for the opamp
* to function. The pin is connected to P2.7
* by setting P2.7 high the opamp is enabled,
* low the opamp is disabled
************************************/
/*
void opamp_enable(int x){
  P2DIR |= BIT7; // Set P2.7 to output direction
    if(x==1){
    P2OUT |= BIT7;  // set P2.7 high. Enables Opamp
    }
*/

/**************************************
* Update LCD Subroutine
**************************************/
void update_lcd(void){
    lcd_char(0,ones + '0');
    lcd_char(1,tens + '0');
    lcd_char(2,hundreds + '0');
}

/**************************************
* Convert Value Subroutine:
* Convert from voltage to sensor value.
* Formulas usually available in datasheet
* for specific sensors.
***************************************/
float convert_value(float voltage){
  float value;
  value = 14.609*pow(voltage,4)-38.65*pow(voltage,3)+47.017*pow(voltage,2)+10.847*voltage-0.2188; 
  return value;
}

/***************************************
* Extract Digits Subroutine:
* The LCD driver requires that each digit
* be presented to the LCD individually. i.e.
* if you want to display 3.14 on the LCD 3, 1,
* and 4 must be held in seperate variables.
* This algorithm assumes only positive values....
* xxx.xx can be represented
****************************************/
void extract_digits(float converted){
    hundreds = (int)converted / 100; // extract hundreds digit
    tens = (int)((converted - (hundreds*100)) / 10); // extract tens digit 
    ones = (int)converted - hundreds*100-(tens * 10); // extract ones digit 
}

/************************************
* Interrupt Subroutines
************************************/
// Basic Timer interrupt service routine
#pragma vector=BASICTIMER_VECTOR
__interrupt void basic_timer(void)
{
    // start a conversion
    // when conversion is complete ADC12 interrupt will take place
    ADC12CTL0 |= ADC12SC;
}

// ADC12 Interrupt Service Routine
#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
  ADC0 = ADC12MEM0;         // IFG is cleared
  ADC0temp+=ADC0;          // accumulate values to average
  if(x==Average){          // test if enough values have been collected
    ADC0Averaged=ADC0temp/Average;   // compute the average value
    Voltage=ADC0Averaged*Vref;   // multiply by Vref to obtain voltage representaion
    Voltage=Voltage/4095;  // divide by #quantization levels
    Converted=convert_value(Voltage); // Convert voltage to appropriate units
    extract_digits(Converted); // Extract individual digits
    update_lcd();  // Update the LCD display    
    x=1;      // Reset the averaging loop
    ADC0temp=0;
  }
  else{
    x++;                  
  }
}