/*
 * main.c
 */

#include <msp430.h>
#include <stdint.h>

/*
	output values of the synthesizer lines are inverted
	from the MC145158 as the lines are inverted buffered
	
	Set the outputs with defines so moving ports and pins
	becomes painless.
*/

#define SYNTH_PORT		P1OUT

#define SYNTH_DATA		BIT0
#define SYNTH_CLOCK		BIT1
#define SYNTH_LATCH		BIT2

#define SIZE_SYNTH_REF	15 //reg + ctrl size
#define SIZE_SYNTH_OUT	18 // ditto

//globals
uint16_t wd_flag= 0;

int main(void)
{
	//watchdog 1/4 second interrupts
	WDTCTL= WDT_ADLY_250;
	//enable the watchdog interrupt
	IE1= WDTIE;

    P1DIR|= SYNTH_DATA | SYNTH_CLOCK | SYNTH_LATCH; //synthesizer data/clock/latch
    P1OUT|=  SYNTH_DATA | SYNTH_CLOCK | SYNTH_LATCH; //init all high, low at RF board

    P1DIR|= BIT6; //home of green launchpad led

    uint16_t reg_ref;
    uint16_t test_ref= 2880;

	_enable_interrupt( );
    for( ; ; )
    {
    	if( ! wd_flag )
    		continue;

    	reg_ref= test_ref << 2;		//14.4Mhz / 2880 = 5Khz
    	reg_ref|= 0x0002;	//control bit high for reference register;

    	uint16_t i= 0;
    	for( ; i < SIZE_SYNTH_REF; ++i )
    	{
    		if( reg_ref & 0x8000 )
    			SYNTH_PORT&= ~SYNTH_DATA;
    		else
    			SYNTH_PORT|= SYNTH_DATA;

       		SYNTH_PORT&= ~SYNTH_CLOCK;
    		SYNTH_PORT|= SYNTH_CLOCK;

    		reg_ref<<= 1;
    	}
    	//now latch in ref buffer
   		SYNTH_PORT&= ~SYNTH_LATCH;
		SYNTH_PORT|= SYNTH_LATCH;

		//blink the led
		P1DIR^= BIT6;
    	wd_flag= 0;
    }
}

#pragma vector=WDT_VECTOR
__interrupt void wdt_interrupt( )
{
	wd_flag= 1;
}