7 servos and ADC running on MSP430 LaunchPad

servos.c

/*
  Freeware. source [email protected]

  ADC pin:          P1.0
  PWM signal pin:   P1.2

  ADC signal is just a light sensor with a 1K resistor to 3.3V

*/

#include <msp430g2231.h>

#define servoCount  7
#define pwmPin0     0x01
#define oneMS       1000

volatile int ADCdata;

int state = 0;
int curServo = 0;
int pinMask = pwmPin0;
int servoLoc[servoCount] = {500,500,500,500,500,500};
int incArray[servoCount] = {7,22,34,58,72,96};

void main(void)
{
  WDTCTL = WDT_MDLY_0_5;                     // WDT ~0.5ms interval timer
  IE1 |= WDTIE;                             // Enable WDT interrupt
  
  // ADC
  ADC10CTL0 = ADC10SHT_2 + ADC10ON;         // sample and hold 16 cycles, ref on
  ADC10AE0 |= INCH_1;                       // P1.0 ADC option select
  ADC10DTC1 = 0x002;                        // 2 conversions
    
  // first pin and [count] consecutive to out
  P1DIR |= ((1 << servoCount) - 1) * (pwmPin0 << 1);
  P1OUT = 0;                               // set all out pins to 0
  
  BCSCTL1 = CALBC1_1MHZ;	            // Running at 1 MHz
  DCOCTL = CALDCO_1MHZ;  
  
  TACTL = MC_0; // off

  while(1)
  {
    __bis_SR_register(LPM0_bits + GIE);     // LPM0, WDT_ISR will force exit
    
    if((state % 4 == 0) && (state < servoCount * 4))
    {
      curServo = state >> 2;
      pinMask = (1 << curServo) * (pwmPin0 << 1);
      
      if(curServo == (servoCount - 1)) // special case ADC controlled servo
      {
        // adc10 is 10 bit, so 0-1024. 1100 is about 1ms, so it works out without scaling.
        servoLoc[curServo] = (ADCdata - 450) * 5;
      }
      else // these just go up and down at different rates
      {
        servoLoc[curServo] += incArray[curServo];
        
        if( (servoLoc[curServo] >= 900) || (servoLoc[curServo] <= 100) )
        {
          if(curServo == 0)
          {
            curServo = 0;
          }
          incArray[curServo] = -incArray[curServo];
        }
      }
        
      // turn on out pin, timerA reaching TACCR0 will fire an event that turns it off
      P1OUT |= pinMask;
      // count 1ms plus 0-1ms pulses on aclk which is calibrated 1MHz
      TACCR0 = servoLoc[curServo] + oneMS;
      TACTL = TASSEL_2 + MC_1 + TAIE + TACLR + OUT;       // ACLK, upmode, interrupt enabled 
      TACCTL0 |= CCIE; 
    }
    else if(state == 30) // read analog input before wrap around at 40 0.5ms counts
    {
        ADC10SA = (unsigned int)&ADCdata;     // store data here  
        ADC10CTL0 |= ENC + ADC10SC;           // Start sampling
    }
    
    state++;
    if(state >= 40)
    {
      state = 0;
    }
    
  }
}

#pragma vector = TIMERA0_VECTOR
__interrupt void CCR0_ISR(void) 
{
  //TACCTL0 &= ~CCIE; 
  TACTL = MC_0;                             // timer A off, interrupt disabled 
  P1OUT = 0; 
}

#pragma vector = WDT_VECTOR
__interrupt void WDT_ISR(void)
{
  __bic_SR_register_on_exit(LPM0_bits);     // Exit LPM0
}