#include <FreqCounter.h>


/**********************************************************
 * Example program SPI-OSC interface with Arduino.
 * 
 * SETUP:    SPI-OSC => Arduino
 * SCK=D13 SDI=D12 SEN=D6 FREQ_INT=D5 OE=ADC3
 * FreqCounter library needed for displaying the frequency set into the ltc6903
 * Frequency is read by the Instance of the FreqCounter Class Library
 * Document: LTC6903 datasheet
 * Updated:  20101230
 * E-mail:   wmoritz@aaahawk.com 
 * Web Page: www.eastco-inc.com
 * Bill Moirtz
 * (C) Copyright 2010 All Rights Reserved
 **********************************************************/

const int SEN = 6;  //Serial Enable for ltc6903
const int SCK = 13;  //Serial Clock for clocking in data
const int SDI = 12;  //Serial Data Input, D15 first
const int OE = A3;  //Enable Output using a AD pin
word Word=0;      //shifting word sent to ltc6903
long int frq;    //read the frequency from D5 input pin
word Oct=12;    //From Linear Technology Spec Sheet page 7
word DAC=707;	//Or you can calculate these values yourself

/*
Get everyone set up to an initial state
*/
void setup() 
{
  Serial.begin(9600); //set normal serial communications
  pinMode(SEN, OUTPUT); //define SEN enable
  pinMode(SCK, OUTPUT);  //define SCK clock
  pinMode(SDI, OUTPUT);  //define SDI data
  digitalWrite(SEN,HIGH);  //set safely high
  digitalWrite(SCK,HIGH);  //set safely high
  digitalWrite(SDI,HIGH);  //set safely high
  pinMode(OE, OUTPUT); //set OE of the ltc6903
  ltc6903(Oct,DAC); //Set Freq from Linear Technology Spec Sheet page 7
  delay(1); //wait one...
  digitalWrite(OE, HIGH); //Turn on the output frequency
}
/*
Display the Frquency in the Serial Monitor by INT1 input
tied to ltc6903's output pin 
*/
void loop() 
{
  FreqCounter::f_comp= 8;             // Set compensation to 12
 FreqCounter::start(100);            // Start counting with gatetime of 10ms
 while (FreqCounter::f_ready == 0)      // wait until counter ready
  frq=FreqCounter::f_freq;    // read result
  frq*=10;            //Forget the units make the value full freq.
  Serial.println(frq);    // print result to the monitor

}
/* 
	Get OCT and DAC into shift word
*/
void ltc6903(word oct,word dac)
 {
    Word=oct;                // do OCT first
    Word<<=12;              // move it to D15
    dac<<=2;                //align the DAC value
    Word|=dac;            //OR it in, leave CN1 and CN0 at zero
    Transfer(Word);      //Send word as sdi to ltc6903
}
/*
  Clock the Data Word into the ltc6903 as fast as you can. The D15 
  bit is first and then shift all bits the the left in thru D15 
  location.
*/
void Transfer(word sdi)
{
  int value=0;        //set D15 test value to zero;

  digitalWrite(SEN,LOW); //set Serial Enable True at ltc6903
  for(int i=0;i!=16;i++) //Got 16 bits to clock in
  {
    value=sdi&32768;    //Strip for testing if D15 
    if (value!=0)      // 1?
    {
      digitalWrite(SDI,HIGH); //Set SDI to TRUE
    }
    else
    {
      digitalWrite(SDI,LOW); //Else set to LOW
    }
    digitalWrite(SCK,LOW);  //Drop the clock line
    digitalWrite(SCK,HIGH); //Trigger in the SDI low
    sdi<<=1;            //Shift next bit into D15 position
  }
  digitalWrite(SEN,HIGH);  //deselect serial transfer
  digitalWrite(SDI,HIGH); //put data high as initial state
}