.gitignore

*.o
*.elf

Makefile

CC     = msp430-gcc
CFLAGS = -Os -Wall -g -mmcu=$(MCU)
TARGET = wdt
OBJS   = wdt.o
BIN    = $(TARGET).elf
MCU    = msp430g2553

all: $(OBJS)
	$(CC) $(CFLAGS) -o $(BIN) $(OBJS)

%.o: %.c
	$(CC) $(CFLAGS) -c $<

clean:
	rm -f $(BIN) $(OBJS)
	

wdt.c

#include <msp430g2553.h>
#include <legacymsp430.h>

#define RED_LED BIT0


typedef struct {
  unsigned long every;
  unsigned long last_call; 
  void (*job_ptr) (void);
} jobs;

jobs job_list[4];

unsigned long millis = 0;
int i;

int main(void)
{
    /* Set watchdog timer interval to 32ms */
    WDTCTL = WDT_MDLY_32;

    /* "Interrupt enable 1" for the Watchdog Timer interrupt */
    IE1 |= WDTIE;

    /* Set the LED pin as an output pin */
    P1DIR |= RED_LED;

    /* Turn on LED pin */
    P1OUT |= RED_LED;

    /* Init job list */
    for (i = 0; i < 4; i++)
    {
      job_list[i].every     = 0;
      job_list[i].last_call = 0;
      job_list[i].job_ptr   = 0;
    }

    /* Do nothing...forever */
    while(1) 
    { 
      /* Go into low power mode 0, general interrupts enabled */
      __bis_SR_register( LPM0_bits + GIE );
      /* Wake up here, check for schedule job */
      for (i = 0; i < 4; i++)
      {
        /* if (millis() > job_list[i].last_call + job_list[i].every) {

        } */
      }
      

    }
}

// TODO safe access routine for millis

/* Watchdog Timer interrupt service routine.  The function prototype
 * tells the compiler that this will service the Watchdog Timer, and
 * then the function follows.
 */
interrupt(WDT_VECTOR) watchdog_ISR(void)
{
  millis += 32;
}