Automated Tea Brewer

Code – main.c:	

#include "msp430.h"
#include "DS18B20Lib\DS18B20.h"
//============================Pins definition===================================
//---------------------------------PORT1----------------------------------------
#define BT_RX    BIT1
#define BT_TX    BIT2

//---------------------------------PORT2----------------------------------------
#define DEFAULT  BIT2 
#define BT_KEY   BIT3 
#define LED_G    BIT4 
#define LED_Y    BIT5 
#define SERVO    BIT6

//-----------------------Servo motor definitions--------------------------------
#define SMCLK_CLOCK 1000000
#define PWM_FREQUENCY 50//In Hertz, ideally 50Hz.
#define SERVO_STEPS 180//Maximum amount of steps in degrees (180 is common)
#define SERVO_MIN 1300//The minimum duty cycle for this servo
#define SERVO_MAX 1800//The maximum duty cycle

//=======================Variables definition===================================
DS18B20 sensor(1,3);
signed int temp;//temperature
unsigned int voltage;//battery voltage
unsigned char presence;//temperature sensor presence flag
unsigned int half_sec;//half of the seconds counter
unsigned char led_pwm;//implementation pwm for LEDs
signed int blue,red;//Brightness of blue and red LEDs
char state; //State of the device: 
            //'d'-waiting for data input
            //'w'-waiting for pulling down the tea contaner
            //'e'-error, water is absent or has too low temperature
            //'b'-brewing of the tea
            //'f'-finishing the process and pulling up the tea container
unsigned int init_temp;//temperature to begin the brewing
unsigned int min, sec;//Brewing time (minutes and seconds)
char tx_buf[8] = {0,0,0,'.',0,0,'\r','\n'};//data to be send fo the phone "t__._s"
char rx_buf[20];//data to be received from phone:
               //i _ _ - initial temperature for brewing start
               //m _ _ - brewing time (minutes)
               //s _ _ - brewing time (seconds)
char rec_bytes;//number of bytes received;
unsigned int PWM_Period = SMCLK_CLOCK / PWM_FREQUENCY;//PWM Period for the servo motor
unsigned int *Flash_ptrD;//Pointer to the information segment D of the flash memory

//==========================General purpose functions===========================
//----------------------------System initialization-----------------------------
void init (void)
{
  //---------------Watchdog timer--------------------
  WDTCTL = WDTPW   WDTHOLD;//Stop watchdog timer 
    
  //-----------------Clock system--------------------
  BCSCTL1 = CALBC1_8MHZ;//Set MCLK frequency as 8 MHz
  DCOCTL = CALDCO_8MHZ;//Set MCLK frequency as 8 MHz
  BCSCTL2 |= DIVS_3;//Set SMCLK frequency as 1 MHz
  
  //-----------------I/O pins------------------------
  //------------------PORT1--------------------------
  P1SEL = BT_RX   BT_RX;//Pins BT_RX and BT_TX are 
  P1SEL2 = BT_TX   BT_RX;//controlled by UCSI module
  P1REN = 0;//No internal resistor on the PORT1
  //------------------PORT2--------------------------
  P2SEL = SERVO;//Connect the P2.4 pin to the output of the TA0CCR1 block
  P2SEL2 = 0;//Connect the P2.4 pin to the output of the TA0CCR1 block
  P2DIR = LED_G   LED_Y   SERVO   BT_KEY;//Set the specified pins as outputs
  P2REN = DEFAULT;//Set the internal resistor on pins WAKEUP
  P2OUT = DEFAULT;//Pull-up resistor on pin WAKEUP and pull_down on pin BT_KEY
  P2IES = DEFAULT;//Falling edge interrupt at WAKEUP pin
  P2IE  = DEFAULT;//Interrupt enable from WAKEUP pin
  
  //---------------USCI module for UART mode---------
  UCA0CTL1 |= UCSSEL1;//Set DCO as clocking source for USCI module
  UCA0BR0 = 104;//Set baudrate of 9600 kbaud
  UCA0BR1 = 0;//Set baudrate of 9600 kbaud
  UCA0MCTL = UCBRS_1;//Set baudrate of 9600 kbaud
  UCA0CTL1 &= ~UCSWRST;//USCI module start
  IE2 = UCA0RXIE;//Interrupt enable on receive data
  
  //-------------Timer 1-----------------------------
  TA1CTL = TASSEL_2   ID_3   MC_1   TAIE;//Timer 0 settings:
  //SMCLK for timer clocking
  //Divider is 8, so frequency is 125 kHz
  //Direct mode (counts from 0 to TACCR0)
  TA1CCR0 = 62500;//Timer 0 period is 62500/125000 = 0.5 s
  
  //------------Timer 0 (PWM for servo motor)--------
  TA0CCTL1 = OUTMOD_7;//TACCR1 reset/set
  TA0CTL = TASSEL_2   MC_1;//SMCLK, upmode
  TA0CCR0 = PWM_Period-1;//PWM Period
  TA0CCR1 = SERVO_MIN;//TACCR1 PWM Duty Cycle
  
  //----------Variables initialization---------------
  rec_bytes = 0;
  state = 'd';
  
  //----------Configure DS18B20 sensor---------------
  sensor.SetResolution(9);      //Set DS18B20 resolution as 9 bits (0.5 centigrades)
  sensor.ConversionStart();
  
  //-----------------Set operating mode--------------
  __bis_SR_register(LPM1_bits   GIE);//Low-power mode 4 with interrupts
}

//-----------------------Delay function-----------------------------------------
void delay(unsigned int n)
{
  volatile unsigned int i;
  for (i = 0; i < n; i  );
}

//=======================Interrupt subroutines==================================
//---------------------USCI data receive interrupt------------------------------
#pragma vector=USCIAB0RX_VECTOR
__interrupt void RX_ISR (void) 
{
  rx_buf[rec_bytes] = UCA0RXBUF;//Save received byte in the buffer
  switch (rx_buf[rec_bytes])//check the first received byte
    {
    case 'i'://if got 'i'
      state = 'd';
      P2SEL = SERVO;//Connect the P2.4 pin to the output of the TA0CCR1 block
      TA0CCR1 = SERVO_MIN;//TACCR1 PWM Duty Cycle
      init_temp = (rx_buf[rec_bytes-2]-0x30)*10 (rx_buf[rec_bytes-1]-0x30);//save initial temperature
      break;
    case 'm'://if got 'm'
      min = (rx_buf[rec_bytes-2]-0x30)*10 (rx_buf[rec_bytes-1]-0x30);//save minutes of brewing
      break;  
    case 's'://if got 's'
      sec = (rx_buf[rec_bytes-2]-0x30)*10 (rx_buf[rec_bytes-1]-0x30);//save seconds of brewing
      sec  = min*60;//add the minutes realculated to seconds
      Flash_ptrD = (unsigned int *) 0x1000; //Set pointer to the start address of the segment D
      FCTL1 = FWKEY   ERASE; //Set ERASE bit
      FCTL3 = FWKEY;         //Clear LOCK bit
      *Flash_ptrD = 0;       //Dummy write to erase the segment
      FCTL1 = FWKEY   WRT;   //Set WRT bit
      *Flash_ptrD   = init_temp;  //Write temperarture to the flash memory
      *Flash_ptrD = sec;     //Write seconds to the flash memory
      FCTL1 = FWKEY;         //Clear WRT bit
      FCTL3 = FWKEY   LOCK;  //Set LOCK bit
           
      rec_bytes = 0;//clear buffer counter
      if (temp >= init_temp*9) //If water is hot enough then wait until it get colder
      {
        state = 'w';
      }
      else //If water is 10% colder than is required then set "error" state
      {
        state = 'e';
      }
      break;
    }
  rec_bytes  ;
}

//---------------------PORT2 pin change interrupt-------------------------------
#pragma vector=PORT2_VECTOR
__interrupt void PORT2_ISR (void) 
{
  if (~P2IN & DEFAULT)//if button is pressed
  {
    delay(2000);//Debounce delay
    if (~P2IN & DEFAULT)//if button is still pressed
    {
      while (~P2IN & DEFAULT);//Waiting until button is pressed
      delay (2000);//debounce delay
      if (P2IN & DEFAULT)//if button is released
      {
        if ((state == 'd') || (state == 'f'))  //If data still has not been entered of brewing has been completed
        {
          Flash_ptrD = (unsigned int *) 0x1000;  //Set pointer to the start address of the segment D
          if (*Flash_ptrD != 0xFF) //If data is valid
          {
            init_temp = *Flash_ptrD  ; //Restore temperature form flash memory
            sec = *Flash_ptrD; //Restore seconds form flash memory
            if (temp >= init_temp*9) //If water is hot enough then wait until it get colder
            {
              state = 'w';
            }
            else //If water is 10% colder than is required then set "error" state
            {
              state = 'e';
            }
          }
        }
      }
    }
  }
  P2IFG &= ~DEFAULT;//reset the interrupt flag
}

//-------------------------Timer 1 overflow interrupt---------------------------
#pragma vector=TIMER1_A1_VECTOR
__interrupt void TIMER1_OWF_ISR (void)
{
  unsigned char i;
  half_sec  ;//increase a counter
  switch (half_sec % 4)//repeat each activity one time in two seconds
  {
  case 0:
    if (temp != -990)//if sensor presents
    {
      tx_buf[0]='t';//represents temperature OK
      tx_buf[1]=temp/100 0x30;//tens of the temperature
      tx_buf[2]=(temp/10) 0x30;//ones of the temperature
      tx_buf[4]=temp 0x30;//tenth part of the temperature
    }
    else//otherwise
    {
      tx_buf[0]='e';//represents sensor error
    }
    tx_buf[5]=state;//Device state
    for (i = 0; i < 8; i   )//Loop to transmit the data
    {
      while (~IFG2&UCA0TXIFG);//Wait until transmit buffer is empty
      UCA0TXBUF = tx_buf[i];//Send the next data
    }
    break;
  case 1:
    sensor.ConversionStart();//send "convert temperature" command
    break;
  case 3:
    temp = sensor.GetData10();//read the temperature value
    if (temp>999)//to avoid error (temperature cannot be more than 100 degreees)
      temp = 999;
    break;
  }
  switch (state)
  {
  case 'd': 
    P2OUT &= ~LED_Y; 
    P2OUT &= ~LED_G; 
    P2SEL &= ~SERVO;//Disconnect the P2.4 pin from the output of the TA0CCR1 block
    break;
  case 'w': 
    P2OUT ^= LED_Y; 
    P2SEL &= ~SERVO;//Disconnect the P2.4 pin from the output of the TA0CCR1 block
    if (temp < init_temp*10) //If water is good then start brewing
    {
      half_sec = 0;
      state = 'b';
    }
    break;
  case 'e': 
    P2OUT ^= LED_Y; 
    P2OUT ^= LED_G; 
    P2SEL &= ~SERVO;//Disconnect the P2.4 pin from the output of the TA0CCR1 block
    if (temp >= init_temp*10) //If water is hot enough then wait until it get colder
    {
      state = 'w';
    }
    break;
  case 'b': 
    P2OUT |= LED_Y; 
    P2OUT &= ~LED_G; 
    P2SEL |= SERVO;//Disconnect the P2.4 pin from the output of the TA0CCR1 block
    if (TA0CCR1 < SERVO_MAX)//Pull the tea container down into the cup
     TA0CCR1 =20;
    else              //If tea container is in the cup
    {
      P2SEL &= ~SERVO;//disconnect the P2.4 pin from the output of the TA0CCR1 block  
      P2OUT |= SERVO;
    }
    if (half_sec > 2*sec) //If brewing time is over then finish brewing
    {
      state = 'f';
    }
    break;
  case 'f':
    P2SEL |= SERVO;//Disconnect the P2.4 pin from the output of the TA0CCR1 block
    if (TA0CCR1 > SERVO_MIN)//Get up tea container down into the cup
     TA0CCR1-=20;
    else              //If tea container is out of the cup
    {
      P2SEL &= ~SERVO;//disconnect the P2.4 pin from the output of the TA0CCR1 block  
      P2OUT |= SERVO;
      P2OUT &= ~LED_Y; 
      P2OUT |= LED_G; 
    }  
    break;
  }
  TA1CTL &= ~TAIFG;//reset the interrupt flag;
}

//=======================Main function==========================================
void main( void )
{
  init();  
  while(1);
}