MSP430 Coffeetimer

coffeetimer-msp430.c

/*
 * Coffetimer (safetytimer)
 * 
 * Activated when button (pin 4) is grounded.
 * Connected to a RF - remote control on pin 5 and 6 
 * via a couple of transistors, controling the 
 * coffemakers power outlet.
 * 
 * */

#include  "msp430g2231.h"

#define LONGDELAY (1000000 / (8*8)) * 4
#define SHORTDELAY (1000000 / (8*8*8))
#define POWERONTIME 4500

const int redLed = BIT0;
const int button = BIT4;
const int powerOn = BIT5;
const int powerOff = BIT6;

volatile int powerActive = 0;
volatile unsigned int onTime = 0;
volatile int blinkState = 0;

unsigned int i, y;

void main(void) {

	WDTCTL = WDTPW + WDTHOLD;
	
	P1DIR = ~button; // Button is input, rest output..
	P1OUT &= ~(powerOn | powerOff | redLed);
	
	P1REN |= button; // Pull up
	P1IES |= button; // High to low interrupt
	P1IE  |= button; // Interrupt on button..
	P1IFG = 0; 		 // Clear INT flag
	
	// Use internal occilator as timer source.. / 8.. /8
	BCSCTL1 = CALBC1_1MHZ; // Set range
	DCOCTL = CALDCO_1MHZ;   // SMCLK = DCO = 1MHz
	BCSCTL2 |= DIVS_3; // Divder / 8 for smclk
	TACTL = TASSEL_2 + MC_1 + ID_3 + TACLR; // Timer A, SMCLK src, up mode, divider / 8..
	
	CCTL0 = CCIE; // capture/compare interrupt go!
	CCR0 = SHORTDELAY;
	
	__enable_interrupt();
	
	while(1) {
		powerActive = 0;
		onTime = 0;

		// Go to sleep, wait for button
		P1IFG = 0;
		LPM4;
		
		// Waking up from button push..
		// Blink and power on coffemaker..
		for (i = 0; i < 4; i++) {
			P1OUT ^= redLed | powerOn;
			for (y = 0; y < 40; y++)
				__delay_cycles(40000);
		}
		P1OUT &= ~(redLed | powerOn);
		
		powerActive = 2;
		
		LPM1;
		
		// Waking up from timer.. blink and turn off coffeemaker..
		for (i = 0; i < 12; i++) {
			P1OUT ^= redLed | powerOff;
			for (y = 0; y < 40; y++)
				__delay_cycles(40000);
		}
		P1OUT &= ~(redLed | powerOff);
		
	}
}

// Button interrupt
#pragma vector=PORT1_VECTOR
__interrupt void port1_isr(void)
{
	if (powerActive == 0) {
		
		// Power on coffeemaker..
		powerActive = 1;
		LPM4_EXIT;
		
	} else if (powerActive == 2) {
		
		// Power off coffeemaker ahead of time..
		onTime = POWERONTIME + 1;
		P1OUT &= ~redLed;
		powerActive = 0;
		LPM1_EXIT;
	}
	
	P1IFG = 0;
}

// Timer interrupt, blink twice every few seconds..
#pragma vector=TIMERA0_VECTOR
__interrupt void timera0_isr(void)
{
	if (powerActive != 2)
		return;
		
	CCR0 = (++blinkState % 4) ? SHORTDELAY : LONGDELAY;
	
	if (blinkState % 2)
		P1OUT |= redLed;
	else
		P1OUT &= ~redLed;
	
	onTime += (blinkState % 4) ? 1 : 4;
	
	// Wake from sleep if coffeemaker has been on long enough
	if (onTime > POWERONTIME) {
		P1OUT &= ~redLed;
		powerActive = 0;
		LPM1_EXIT;
	}	
}