package stamp.peripheral.io;

import stamp.core.*;
import stamp.peripheral.io.I2C;


/*
 * I2C Temperature Sensor.
 *
 * This class manipulates a Dallas DS1621 digital thermometer and
 * thermostat IC
 *
 * DS1621(I2C, Adr, OpMode) constructor method I2C is pointer to an I2C object
 * Adr is the I2C device address (read) and OpMode 1 for One shot temp reading
 * 0 for continuous temp reading
 * gettemp() returns temp in C
 * startconv() & stopconv() starts and stops temp conversion within the IC thus
 * lowering its power consumption
 * set1shot(boolean) sets one shot mode
 * setTH(int) & setTL(int) set thermostat trigger and reset temps the Tout pin
 * is configured to be active high in this class
 *
 * @version 1.0 27 August 2004
 * @author Steven Tron
 */

public class DS1621 {

  final static int RTemp = 0xAA;
  final static int TH = 0xA1;
  final static int TL = 0xA2;
  final static int Conf = 0xAC;
  final static int SConv = 0xEE;
  final static int EConv = 0x22;
  final static int Nak = 0x1;
  final static int Ack = 0x0;

  protected I2C ioBus;
  protected int WAddr;
  protected int RAddr;
  protected boolean Mode;
  protected StringBuffer tempval = new StringBuffer(5);

  public DS1621(I2C bus, int Adr, boolean OpMode) {
    this.ioBus = bus;
    this.WAddr = Adr++;
    this.RAddr = Adr;
    this.Mode = OpMode;
    this.set1shot(OpMode);
    }

  private void setreg(int reg) {
    ioBus.start();
    ioBus.write(WAddr);
    ioBus.write(reg);
    }

  public void startconv() {
    setreg(SConv);
    ioBus.stop();
    }

  public void stopconv() {
    setreg(EConv);
    ioBus.stop();
    }

  public void set1shot(boolean tmode) {
    setreg(Conf);
    if (tmode) {
        ioBus.write(3);
        Mode = true;
        }
    else {
        ioBus.write(2);
        Mode = false;
        startconv();
        }
    ioBus.stop();
    }

  public void setTH(int THVal) {
    setreg(TH);
    ioBus.write(THVal);
    ioBus.write(0);
    ioBus.stop();
    }

  public void setTL(int TLVal) {
    setreg(TL);
    ioBus.write(TLVal);
    ioBus.write(0);
    ioBus.stop();
    }

  public String gettemp() {
    int LTemp;
    if (Mode) {
      startconv();
    }
    tempval.clear();
    setreg(RTemp);
    ioBus.start();
    ioBus.write(RAddr);
    tempval.append(ioBus.read(Ack));
    LTemp = ioBus.read(Nak);
    if (LTemp > 0) {
      tempval.append(".5");
      }
    else {
      tempval.append(".0");
      }
    tempval.append("C");
    ioBus.stop();
    if (Mode) {
      stopconv();
    }
    return tempval.toString();
    }
} 