Can anyone help me trim this down? (8,168 of 8,192 used)

Projects Programming
10

Here is some code that I use to read the temperature that does not use a library.
It is much smaller than using the 1 wire library but only works with a single sensor on the bus.
It also does not use any floating point so that saves space as well.

void OneWireReset(int Pin) // reset.  Should improve to act as a presence pulse
{
     digitalWrite(Pin, LOW);
     pinMode(Pin, OUTPUT); // bring low for 500 us
     delayMicroseconds(500);
     pinMode(Pin, INPUT);
     delayMicroseconds(500);
}

void OneWireOutByte(int Pin, byte d) // output byte d (least sig bit first).
{
   byte n;

   for(n=8; n!=0; n--)
   {
      if ((d & 0x01) == 1)  // test least sig bit
      {
         digitalWrite(Pin, LOW);
         pinMode(Pin, OUTPUT);
         delayMicroseconds(5);
         pinMode(Pin, INPUT);
         delayMicroseconds(60);
      }
      else
      {
         digitalWrite(Pin, LOW);
         pinMode(Pin, OUTPUT);
         delayMicroseconds(60);
         pinMode(Pin, INPUT);
      }

      d=d>>1; // now the next bit is in the least sig bit position.
   }
   
}

byte OneWireInByte(int Pin) // read byte, least sig byte first
{
    byte d, n, b;

    for (n=0; n<8; n++)
    {
        digitalWrite(Pin, LOW);
        pinMode(Pin, OUTPUT);
        delayMicroseconds(5);
        pinMode(Pin, INPUT);
        delayMicroseconds(5);
        b = digitalRead(Pin);
        delayMicroseconds(50);
        d = (d >> 1) | (b<<7); // shift d to right and insert b in most sig bit position
    }
    return(d);
}


/*
 * Returns temp in C times 100.
 * i.e. 12.34 degress C is returned as 1234
 */
int getCurrentTemp()
{  
  int HighByte, LowByte, TReading, Tc_100, sign;

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc); // SKIP ROM (broadcast to all devices)
  OneWireOutByte(TEMP_PIN, 0x44); // CONVERT (perform temperature conversion, strong pullup for one sec)

  OneWireReset(TEMP_PIN);
  OneWireOutByte(TEMP_PIN, 0xcc); // SKIP ROM (broadcast to all devices)
  OneWireOutByte(TEMP_PIN, 0xbe); // READ SRATCHPAD

  LowByte = OneWireInByte(TEMP_PIN);
  HighByte = OneWireInByte(TEMP_PIN);
  TReading = (HighByte << 8) + LowByte;
#if 0
  sign = TReading & 0x8000;  // test most sig bit
  if (sign) // negative
  {
    TReading = (TReading ^ 0xffff) + 1; // 2's comp
  }
#endif
  Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25

  return(Tc_100);

	
}

It uses integers so you have to do a small calculation to get things ready to print.
So here is how you use it.

	Tc_100 = getCurrentTemp();
	if(Tc_100 < 0)
	{
		Tc_100 = -Tc_100;
		sign = '-';
	}
	else
	{
		sign = '+';
	}

	if(units == 'F')
		Tc_100 = ((Tc_100 * 9 ) / 5) + 3200;

	T_whole = Tc_100 / 100;  // separate off the whole and fractional portions
	T_fract = Tc_100 % 100;

Tc_100, T_whole, and T_fract are all declared as int
units and sign are declared as char

--- bill