main.c

This a simple example project for the MSP430 series MCU and the GCC port of the mspgcc project. The

/*
see README.txt for details.

chris <[e-mail]>
*/
#include "hardware.h"
#include <stdlib.h>
#include <stdio.h>
#include "lcd.h"

//the font file has no separate header file, it just provides
//the font in this array:
extern const char lcdfont[64];

//redirect stdio to LCD
int putchar(int c) {
    lcdPutc(c);
    return 1;
}

//global vars to store the time
int h, m, s;

/**
This one is executed once a second. it counts seconds, minutes, hours - hey
it shoule be a clock ;-)
it does not count days, but i think you'll get the idea :-)
*/
wakeup interrupt (TIMERA0_VECTOR) INT_TimerA_CCR0(void) {
    CCR0 += ONESECOND;                  //setup next irq
    if (++s > 59) {                     //count seconds, up to one minute
        s = 0;                          //reset seconds and ...
        if (++m > 59) {                 //count miutes, up to one hour
            m = 0;                      //reset minutes and ...
            if (++h > 23) {             //cound hours, up to one day
                h = 0;                  //reset hours and ...
                //++day ...             //don't do anything, could count days here
            }
        }
    }
}

/**
Main function with init an an endless loop that is synced with the
interrupts trough the lowpower mode.
*/
int main(void) {
    int i = 0;

    WDTCTL = WDTCTL_INIT;               //Init watchdog timer

    P1OUT  = P1OUT_INIT;                //Init output data of port1
    P2OUT  = P2OUT_INIT;                //Init output data of port2

    P1SEL  = P1SEL_INIT;                //Select port or module -function on port1
    P2SEL  = P2SEL_INIT;                //Select port or module -function on port2

    P1DIR  = P1DIR_INIT;                //Init port direction register of port1
    P2DIR  = P2DIR_INIT;                //Init port direction register of port2

    P1IES  = P1IES_INIT;                //init port interrupts
    P2IES  = P2IES_INIT;
    P1IE   = P1IE_INIT;
    P2IE   = P2IE_INIT;

    BCSCTL1 |= DIVA0 | DIVA1;           //setup divider for RTC
    TACTL  = TACTL_INIT;                //setup timer (still stopped)
    CCR0   = ONESECOND;                 //setup first RTC irq
    CCTL0  = CCIE;                      //enable compare interrupts
    CCTL1  = 0;                         //the other modules are not used
    CCTL2  = 0;                         //...
    TACTL  |= MC1;                      //start timer

    eint();                             //enable interrupts

    P2OUT |= LED;                       //light LED during init
    lcdOn();                            //reset sequence
    lcdInit();                          //setup LCD modes
    lcdDownloadFont(lcdfont, sizeof(lcdfont));
    P2OUT &= ~LED;                      //switch off LED
    puts("Hi, I'm a clock");            //say hello

    while (1) {                         //main loop, never ends...
        lcdInstr(LCD_LINE2);
        //show the clock
        //as we are synced with the interrupt, its save to read h,m,s
        //otherwise a dint..eint around the following line would be
        //very helpful to prevent bogus values
        printf("%02d:%02d:%02d", h, m, s);
        //now show the bargraph. it hasn't to do much with a clock
        //but we want to show the feature here...
        lcdInstr(LCD_LINE2+15);
        putchar(i);
        if (++i >= 8) i = 0;            //lets show all 8 downloadable chars
        LPM0;                           //sync, wakeup by irq
    }
}