bicolorclock.c

// 2010 Kenneth Finnegan
// http://kennethfinnegan.blogspot.com/
// Two color blink clock running on MSP430 controller

#include "msp430G2101.h"

#define BLINK_ON 3000	
#define BLINK_OFF 1500
#define BLINK_SPACE 6000

volatile unsigned char time[4];
volatile unsigned char mode;

// FUNCTIONS
void displayNum (int c);
void displayTime(void);
void displayTwiddle(void);
void pause (int c);

void main(void) {
	WDTCTL = WDTPW + WDTHOLD;	// Stop Watchdog Timer
	
	BCSCTL3 = (BCSCTL3 & ~(XCAP0 | XCAP1)) | XCAP_1; // 6pF xtal
	BCSCTL2 = 0xF8; // MCLK:LFXT1CLK/8 SMCLK:LFXT1CLK
	
	
	P1DIR = 0x41;
	P1OUT = 0x0F; // pull up resistors
	P1REN = 0x0E; // pull up resistors enable
	P1IE = 0x08; // Setup P1.3 for interrupt
	P1IES = 0x08; // High -> Low transistion
	P1IFG &= ~0x08; // Clear int flag
	
	CCTL0 = CCIE;
	CCR0 = 0;
	TACCR0 = 0x7FFF; // Period of 32767 + 1
	TACTL = 0x0211; // Timer_A: SMCLK, UP MODE, TAIE
	
	while(1) {
		mode = 0;
		_BIS_SR(LPM1_bits + GIE);
		switch (mode) {
			case 0x06: // display time
				displayTime();
				break;
			case 0x04: // display hours
				
				if (time[3]) displayTwiddle();
				pause(BLINK_SPACE);
				displayNum(time[2]);
				break;
			case 0x02: // increment minutes
				displayNum(time[1]);
				break;
		}
	}
}

#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A (void) {
	//P1OUT ^= 1;
	time[0] = (time[0] + 1) % 60;
	if (time[0] == 0) { // new minute
		time[1] = (time[1] + 1) % 60;
		if (time[1] == 0) { // new hour
			time[2] = (time[2] + 1) % 12;
			time[2] = time[2]?time[2]:12;
			if (time[2] == 12) { // new AM/PM
				time[3] = !time[3];
			}
		}
	}		
}

#pragma vector=PORT1_VECTOR
__interrupt void Port_1 (void) {
	mode = P1IN & 0x06;
	LPM1_EXIT; // Wake up the main loop
	
	switch (mode) { // Needs debounce!
		case 0x04:
			time[2] = (time[2] + 1) % 12;
			time[2] = time[2]?time[2]:12;
			if (time[2] == 12) { // new AM/PM
				time[3] = !time[3];
			}
			break;
		case 0x02:
			time[1] = (time[1] + 1) % 60;
			time[0] = 0;
			break;
	}
		
	P1IFG = 0; // Clear int flag
}


void displayTime(void) {
	if (time[3]) { // twiddle on PM
		displayTwiddle();
	}
	
	pause(BLINK_SPACE);
	displayNum(time[2]);
	
	pause(BLINK_SPACE);
	displayNum(time[1]);
}

void displayNum (int c) {
	int i;
	for (i=c/10; i; i--) {
		P1OUT |= 0x40;
		pause(BLINK_ON);
		P1OUT &= ~0x40;
		pause(BLINK_OFF);
	}
	if ((c%10) > 4) {
		P1OUT |= 0x41;
		pause(BLINK_ON);
		P1OUT &= ~0x41;
		pause(BLINK_OFF);
	}
	for (i=c%5; i; i--) {
		P1OUT |= 0x1;
		pause(BLINK_ON);
		P1OUT &= ~0x1;
		pause(BLINK_OFF);
	}
	P1OUT &= ~(0x41);
}

void displayTwiddle(void) {
	int i;
	for (i=0; i<2; i++) {
		P1OUT |= 0x40;
		P1OUT &= ~(0x01);
		pause(BLINK_ON);
		P1OUT |= 0x01;
		P1OUT &= ~(0x40);
		pause(BLINK_ON);
	}
	P1OUT &= ~(0x41);
}

void pause (int c) {
	volatile unsigned int t = c;
	do { t--;} while (t);
}