Write a program for the MSP430 using Energia placing an interrupt on the push 2

Question

Write a program for the MSP430 using Energia placing an interrupt on the push 2 button so that the first time the button is pushed the red LED should turn on for 1 second and then turn off. The second time the button is pushed the red LED should turn on for 1 second, turn off for 1 second, turn back on for 1 second, and off again. The third time the button is pushed the green LED should turn on for 1 second and then turn off. The fourth time the button is pushed the green LED should turn on for 1 second, turn off for 1 second, turn back on for 1 second, and off again. The fifth time the button is pushed the red LED should turn on for 1 second and then turn off. The sixth time the button is pushed the red LED should turn on for 1 second, turn off for 1 second, turn back on for 1 second, and off again…. (Etc. etc. etc.)

Explanation / Answer

#include <io.h>
#include <string.h>

#define   RED_LED   BIT0
#define   GRN_LED   BIT6

#define   BUTTON    BIT3

#define   TXD       BIT1
#define   RXD       BIT2

#ifndef CALDCO_16MHZ_
#define CALDCO_16MHZ_         0x10F8    /* DCOCTL Calibration Data for 16MHz */
const_sfrb(CALDCO_16MHZ, CALDCO_16MHZ_);
#define CALBC1_16MHZ_         0x10F9    /* BCSCTL1 Calibration Data for 16MHz */
const_sfrb(CALBC1_16MHZ, CALBC1_16MHZ_);
#endif

#ifndef CALDCO_12MHZ_
#define CALDCO_12MHZ_         0x10FA    /* DCOCTL Calibration Data for 12MHz */
const_sfrb(CALDCO_12MHZ, CALDCO_12MHZ_);
#define CALBC1_12MHZ_         0x10FB    /* BCSCTL1 Calibration Data for 12MHz */
const_sfrb(CALBC1_12MHZ, CALBC1_12MHZ_);
#endif

#ifndef CALDCO_8MHZ_
#define CALDCO_8MHZ_          0x10FC    /* DCOCTL Calibration Data for 8MHz */
const_sfrb(CALDCO_8MHZ, CALDCO_8MHZ_);
#define CALBC1_8MHZ_          0x10FD    /* BCSCTL1 Calibration Data for 8MHz */
const_sfrb(CALBC1_8MHZ, CALBC1_8MHZ_);
#endif

/* Ticks per bit, and ticks per half.
* 2400 bps -> 52
*/
#define   TPB      52
#define   TPH      (TPB/2)

unsigned char *data;
unsigned int bytestosend=0;
unsigned int TXWord = 0;
unsigned int txbitcnt = 0;

/* for converting hex values to characters */
unsigned char hex[] = "0123456789ABCDEF";

/* prototypes */
unsigned char set_dco_c(unsigned int delta);
void initUart( void );
int sendString( char *str );
void report_data( void );

unsigned int calbc1_1mhz, caldco_1mhz,
             calbc1_8mhz, caldco_8mhz,
             calbc1_12mhz, caldco_12mhz,
             calbc1_16mhz, caldco_16mhz;

/************ main program starts here ******************/
void main( void ) {
    /* stop the watchdog timer */
    WDTCTL = WDTPW + WDTHOLD;

    /* LEDs off for now, but ready */
    P1DIR |= RED_LED+GRN_LED;
    P1OUT &= ~ (RED_LED + GRN_LED );

    /* start from the 1Mhz calibration values */
    BCSCTL1 = CALBC1_1MHZ;
    DCOCTL = CALDCO_1MHZ;

    /* calculate our own 1Mhz values */
    if( !set_dco_c( 244 )) {
        calbc1_1mhz = BCSCTL1;
        caldco_1mhz = DCOCTL;
    } else {
        calbc1_1mhz = caldco_1mhz = 0xff;
    }

    /* calculate our own 8Mhz values */
    if( !set_dco_c( 1953 )) {
        calbc1_8mhz = BCSCTL1;
        caldco_8mhz = DCOCTL;
    } else {
        calbc1_8mhz = caldco_8mhz = 0xff;
    }

    /* calculate our own 12Mhz values */
    if( !set_dco_c( 2929 )) {
        calbc1_12mhz = BCSCTL1;
        caldco_12mhz = DCOCTL;
    } else {
        calbc1_12mhz = caldco_12mhz = 0xff;
    }

    /* calculate our own 16Mhz values */
    if( !set_dco_c( 3662 )) {
        calbc1_16mhz = BCSCTL1;
        caldco_16mhz = DCOCTL;
    } else {
        calbc1_16mhz = caldco_16mhz = 0xff;
    }

    /* get ready to transmit to the computer */
    initUart();

    /* turn on red LED so we know calibration is done */
    P1OUT |= RED_LED;

    /* We'll use the button to let the chip know we're ready to communicate.
     * Button direction is receive, clear interrupt flag
     */
    P1DIR &= ~BUTTON;
    P1IFG &= ~BUTTON;

    while( 1 ) {
        /* done -- go to sleep and wait for button interrupt to report to PC */
        P1IE |= BUTTON;
        __bis_SR_register( LPM3_bits + GIE );

        P1OUT ^= RED_LED;
        report_data();
    }
}

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