/*
 * Babby's First MSP430G2xx Program
 * Toggle an LED on the Launchpad on button press
 *
 * Copyright (c) 2011, Chris Sammis (http://csammisrun.net)
 * Source released under the MIT License (http://www.opensource.org/licenses/mit-license.php)
 *
 */

#include <io.h>
#include <signal.h>

unsigned char ucWdt_Debounce_Pin = 0x00;

void debounce(unsigned char ucPin);

int main()
{
    // Stop the watchdog timer
    WDTCTL = WDTPW + WDTHOLD;   // WDTPW is a Magic Number (MSP430G2XX user guide section 10.3)

    // Initialize the clocks
    // cstodo what is actually happening here?
    BCSCTL1  = CALBC1_1MHZ;
    DCOCTL   = CALDCO_1MHZ;
    BCSCTL2 &= ~DIVS_3;

    // Configure output to the Launchpad green LED
    P1DIR  = BIT6 + BIT0;  // Set P1.6 (green LED on Launchpad) to output
    P1OUT |= BIT6;  // Set P1.6 high to turn on the LED
    
    P1OUT &= ~BIT0;  //debug Turn off red LED
    
    // Configure input from the Launchpad switch (P1.3)
    P1IE   = BIT3;  // Enable interrupts from P1.3
    P1OUT |= BIT3;  // Set P1.3 output to high...
    P1REN  = BIT3;  // ...and then enable the pull resistor (P1OUT.3 high specifies "up")


    __bis_SR_register(CPUOFF | GIE); // Switch to LPM0 and enable interrupts

    return 0;
}

// General ISR to switch interrupts from P1
interrupt(PORT1_VECTOR) p1_isr()
{
    // P1IFG has bits set indicating which pin caused the interrupt
    switch (P1IFG)
    {
        case BIT3:
            debounce(BIT3);
            
            // Toggle P1.6's output
            P1OUT ^= BIT6;
            break;

        default:
            P1IFG = 0; // Unhandled interrupt, just reset the flag
            break;
    }
}

// General debounce routines using the WDT
//
// Debouncing disables the input interrupt briefly so that the ISR
// can continue without being re-entered unexpectedly.
void debounce(unsigned char ucPin)
{
    P1IFG &= ~ucPin;    // Clear the pending interrupt flag corresponding to the pin
    P1IE &= ~ucPin;     // Disable this interrupt (will be re-enabled at end of debounce)
    ucWdt_Debounce_Pin = ucPin; // Store the pin so it can be accessed in the WDT ISR

    // Configure the WDT to fire off after SMCLK (1MHz) / 512 = 29ms
    WDTCTL = (WDTPW + WDTTMSEL + WDTCNTCL + WDTIS1);

    P1OUT |= BIT0; // Debug: Turn on the red LED until the WDT_isr

    IFG1 &= ~WDTIFG;    // Clear the WDT interrupt flag
    IE1 |= WDTIE;       // Enable WDT interrupts
}

// WDT interrupt vector: re-enables interrupts on P1.ucWdt_Debounce_Pin
interrupt(WDT_VECTOR) wdt_isr()
{
    P1OUT &= ~BIT0; // Debug: Turn off the red LED

    IE1 &= ~WDTIE;   // Disable the WDT interrupt
    IFG1 &= ~WDTIFG; // Clear the WDT interrupt flag

    WDTCTL = WDTPW + WDTHOLD; // Stop the WDT again
    P1IE |= ucWdt_Debounce_Pin; // Re-enable the interrupts on the debounced pin
}
//eof