/* ATtiny85 as an I2C Master  Ex1          BroHogan                      1/21/11
 * I2C master reading DS1621 temperature sensor. (display with leds)
 * SETUP:
 * ATtiny Pin 1 = (RESET) N/U                      ATtiny Pin 2 = (D3) LED3
 * ATtiny Pin 3 = (D4) to LED1                     ATtiny Pin 4 = GND
 * ATtiny Pin 5 = SDA on DS1621                    ATtiny Pin 6 = (D1) to LED2
 * ATtiny Pin 7 = SCK on DS1621                    ATtiny Pin 8 = VCC (2.7-5.5V)
 * NOTE! - It's very important to use pullups on the SDA & SCL lines!
 * DS1621 wired per data sheet. This ex assumes A0-A2 are set LOW for an addeess of 0x48
 * TinyWireM USAGE & CREDITS: - see TinyWireM.h
 * NOTES:
 * The ATtiny85 + DS1621 draws 1.7mA @5V when leds are not on and not reading temp.
 * Using sleep mode, they draw .2 @5V @ idle - see http://brownsofa.org/blog/archives/261
 */

#include <USIWire.h>                 // I2C Master lib for ATTinys which use USI

#define ADDR   0x26              
#define LED1_PIN         7              // ATtiny Pin 3
#define LED2_PIN         8              // ATtiny Pin 6
int rec=0;

void setup(){
  pinMode(LED1_PIN,OUTPUT);
  pinMode(LED2_PIN,OUTPUT);
  
  Wire.begin();                    // initialize I2C lib
  Blink(LED1_PIN,2);                    // show it's alive
  delay (1000);
}


void loop(){
   Wire.beginTransmission(ADDR);
   Wire.write(B00000001);            // Send 1 byte
   Wire.endTransmission();
   Blink(LED1_PIN,2);               // show it's alive and sending
  delay (1000);                    // wait a few sec before next reading
}

void Blink(byte led, byte times){ // poor man's GUI
  for (byte i=0; i< times; i++){
    digitalWrite(led,HIGH);
    delay (400);
    digitalWrite(led,LOW);
    delay (175);
  }
}