mirror of https://github.com/noisymime/Arduino.git
133 lines
2.9 KiB
C++
133 lines
2.9 KiB
C++
//
|
|
// Continually measures temperatures at three points using the Dallas DS18B20 on three
|
|
// separate Arduino pins.
|
|
//
|
|
// Uses the parasitic power mode
|
|
//
|
|
// Displays to a serial LCD operating at 9600 baud.
|
|
//
|
|
// Arduino Board DS18B20
|
|
//
|
|
// +5 VDC
|
|
// |
|
|
// 4.7K
|
|
// 8 ---------------- |----- 2 (DQ) Note that terms 1 and 3 are grounded.
|
|
//
|
|
// 7 ---- same as above
|
|
// 6 ---- same as above
|
|
//
|
|
// Tx ---------------------------- To Serial LCD (LCD #117)
|
|
//
|
|
// Peter H Anderson, Baltimore, MD, May 5, '07
|
|
|
|
|
|
void setup()
|
|
{
|
|
int n, dev_channel[3] = {8, 7, 6}, _1W_Pin;
|
|
|
|
for (n=0; n<1; n++)
|
|
{
|
|
_1W_Pin = dev_channel[n];
|
|
digitalWrite(_1W_Pin, LOW);
|
|
pinMode(_1W_Pin, INPUT); // sets the digital pin as input (logic 1)
|
|
}
|
|
Serial.begin(9600);
|
|
delay(100);
|
|
Serial.print("?B40"); // set backlight intensity
|
|
delay(100);
|
|
}
|
|
|
|
void loop()
|
|
{
|
|
int n, dev_channel[3] = {8, 7, 6}, _1W_Pin;
|
|
int HighByte, LowByte, TReading, SignBit, Tc_100, Whole, Fract;
|
|
|
|
for (n=0; n<3; n++)
|
|
{
|
|
_1W_Pin = dev_channel[n];
|
|
OneWireReset(_1W_Pin);
|
|
OneWireOutByte(_1W_Pin, 0xcc, 0);
|
|
OneWireOutByte(_1W_Pin, 0x44, 1); // perform temperature conversion, strong pullup for one sec
|
|
|
|
OneWireReset(_1W_Pin);
|
|
OneWireOutByte(_1W_Pin, 0xcc, 0);
|
|
OneWireOutByte(_1W_Pin, 0xbe, 0);
|
|
|
|
LowByte = OneWireInByte(_1W_Pin);
|
|
HighByte = OneWireInByte(_1W_Pin);
|
|
TReading = (HighByte << 8) + LowByte;
|
|
SignBit = TReading & 0x8000; // test most sig bit
|
|
if (SignBit) // negative
|
|
{
|
|
TReading = (TReading ^ 0xffff) + 1; // 2's comp
|
|
}
|
|
Tc_100 = (6 * TReading) + TReading / 4; // multiply by (100 * 0.0625) or 6.25
|
|
|
|
Whole = Tc_100 / 100; // separate off the whole and fractional portions
|
|
Fract = Tc_100 % 100;
|
|
|
|
if (n==0) // if its the first time, clear the LCD
|
|
{
|
|
Serial.print("?f");
|
|
delay(100);
|
|
}
|
|
|
|
if (SignBit) // If its negative
|
|
{
|
|
Serial.print("-");
|
|
}
|
|
Serial.print(Whole);
|
|
Serial.print(".");
|
|
if (Fract < 10)
|
|
{
|
|
Serial.print("0");
|
|
}
|
|
Serial.print(Fract);
|
|
Serial.print("?n");
|
|
}
|
|
delay(5000); // 5 second delay. Adjust as necessary
|
|
}
|
|
|
|
void OneWireReset(int _1W_Pin) // reset. Should improve to act as a presence pulse
|
|
{
|
|
digitalWrite(_1W_Pin, LOW);
|
|
pinMode(_1W_Pin, OUTPUT); // bring low for 500 us
|
|
delayMicroseconds(500);
|
|
pinMode(_1W_Pin, INPUT);
|
|
delayMicroseconds(500);
|
|
}
|
|
|
|
void OneWireOutByte(int _1W_Pin, byte d, byte strong) // output byte d (least sig bit first).
|
|
{
|
|
byte n;
|
|
|
|
for(n=8; n!=0; n--)
|
|
{
|
|
if ((d & 0x01) == 1) // test least sig bit
|
|
{
|
|
digitalWrite(_1W_Pin, LOW);
|
|
pinMode(_1W_Pin, OUTPUT);
|
|
delayMicroseconds(5);
|
|
pinMode(_1W_Pin, INPUT);
|
|
delayMicroseconds(60);
|
|
}
|
|
else
|
|
{
|
|
digitalWrite(_1W_Pin, LOW);
|
|
pinMode(_1W_Pin, OUTPUT);
|
|
delayMicroseconds(60);
|
|
pinMode(_1W_Pin, INPUT);
|
|
}
|
|
|
|
d=d>>1; // now the next bit is in the least sig bit position.
|
|
}
|
|
if(strong)
|
|
{
|
|
digitalWrite(_1W_Pin, HIGH); // One sec of strong +5 VDC
|
|
pinMode(_1W_Pin, OUTPUT);
|
|
delay(1000);
|
|
pinMode(_1W_Pin, INPUT);
|
|
digitalWrite(_1W_Pin, LOW);
|
|
}
|
|
}
|