Using a DS1077 Programmable Oscillator with Arduino

I bought a DS1077 Programmable Oscillator a while back for a project but only recently blew the dust off it to try to get it going. It had been a little while since I had talked to components through I2C and I had some trouble talking to it right away. In case anyone else is having trouble talking to it with an Arduino I thought I'd post my code to speed them along.

Just as a first point, I've never been 100% sure if I needed to use pull-up resistors with I2C on an Arduino, as most of the time I haven't needed them. This time though they seemed to make a difference. I used 4.7kohm resistors to pull up SDA and SCL.

Here's the code:

	#include <Wire.h>
	const int ds_address = 0xB0 >> 1; //DS1077 default address
	const byte freq_pin = 7; //read frequency on this pin
	void setup() {
	Wire.begin();
	Serial.begin(9600);
	pinMode(freq_pin, INPUT);
	//Initialize DS1077
	i2c_write(ds_address, 0x0D, 0x08);
	//delay(500);
	i2c_write(ds_address, 0x02, 0x18, 0x00);
	//delay(500);
	i2c_write(ds_address, 0x01, 0xFF, 0xC0);
	//delay(500);
	i2c_write(ds_address, 0x3F);
	//delay(500);
	}
	void loop() {
	// read the frequency
	Serial.println(getFrequency(freq_pin));
	}
	void i2c_write(int device, byte address) {
	Wire.beginTransmission(device); //start transmission to device
	Wire.write(address); // send register address
	Wire.endTransmission(); //end transmission
	}
	void i2c_write(int device, byte address, byte val1) {
	Wire.beginTransmission(device); //start transmission to device
	Wire.write(address); // send register address
	Wire.write(val1); // send value to write
	Wire.endTransmission(); //end transmission
	}
	void i2c_write(int device, byte address, byte val1, byte val2) {
	Wire.beginTransmission(device); //start transmission to device
	Wire.write(address); // send register address
	Wire.write(val1); // send value to write
	Wire.write(val2); // send value to write
	Wire.endTransmission(); //end transmission
	}
	long getFrequency(int pin) {
	#define SAMPLES 4096
	long freq = 0;
	for(unsigned int j=0; j<SAMPLES; j++)
	freq+= 500000/pulseIn(pin, HIGH, 250000);
	return freq / SAMPLES;
	}

view raw DS1077.c hosted with ❤ by GitHub

A bunch of credit goes to the post on Hack A Day as well as the post on Semyon Tushev's blog (links below). I should note that I didn't really spend much time with the registers as I only wanted to get 16.2kHz out of it (for now) so I won't be very knowledgeable about that stuff.

References

Parts: 133MHz-16.2kHz programmable oscillator (DS1077)
http://www.hackaday.com/2008/11/28/parts-133mhz-162khz-programmable-oscillator-ds1077/

Measuring frequency with Arduino
http://tushev.org/articles/electronics/43-measuring-frequency-with-arduino

DS1077 Programmable Oscillator Breakout - 16.2kHz to 133MHz
https://www.sparkfun.com/products/9116

Arduino Forum: Need for I2C pullup resistors
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1286192280