+ initial version 0.1.00

+ two demo sketches
+ short readme.txt

libraries/MAX31855/MAX31855.cpp

@@ -0,0 +1,87 @@
+//
+//    FILE: MAX31855.cpp
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.00
+// PURPOSE: MAX31855 - Thermocouple
+//    DATE: 2014-01-01
+//     URL:
+//
+// Released to the public domain
+//
+
+#include "MAX31855.h"
+
+MAX31855::MAX31855(uint8_t sclk, uint8_t cs, uint8_t miso) 
+{
+    _sclk = sclk;
+    _cs = cs;
+    _miso = miso;
+}
+
+void MAX31855::begin()
+{
+    pinMode(_cs, OUTPUT);
+    digitalWrite(_cs, HIGH);
+
+    pinMode(_sclk, OUTPUT);
+    pinMode(_miso, INPUT);
+}
+
+uint8_t MAX31855::read()
+{
+    uint32_t value = _read();
+    
+    // process status bit 0-2
+    _status = value & 0x0007;
+    value >>= 3;
+
+    // reserved bit 3
+    value >>= 1;
+    
+    // process internal bit 4-15
+    _internal = (value & 0x07FF) * 0.0625;
+    if (value & 0x0800) _internal *= -1;
+    value >>= 12;
+    
+    // Fault bit ignored as we have the 3 status bits
+    // _fault = value & 0x01;
+    value >>= 1;
+    
+    // reserved bit 17
+    value >>= 1;
+        
+    // process temperature bit 18-31
+    _temperature = (value & 0x1FFF) * 0.25;
+    if (value & 0x2000) _temperature *= -1;
+    
+    return _status;
+}
+
+
+uint32_t MAX31855::_read(void) 
+{
+    uint32_t value = 0;
+
+    digitalWrite(_sclk, LOW);
+    delayMicroseconds(1000);
+    digitalWrite(_cs, LOW);
+    delayMicroseconds(1000);
+
+    for (int8_t i=31; i>=0; i--)
+    {
+        digitalWrite(_sclk, LOW);
+        delayMicroseconds(1000);
+        
+        value <<= 1;
+        if (digitalRead(_miso) == HIGH) value += 1;
+        
+        digitalWrite(_sclk, HIGH);
+        delayMicroseconds(1000);
+    }
+
+    digitalWrite(_cs, HIGH);
+    
+    return value;
+}
+
+// END OF FILE

libraries/MAX31855/MAX31855.h

@@ -0,0 +1,49 @@
+#ifndef MAX31855_H
+#define MAX31855_H
+//
+//    FILE: MAX31855.h
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.00
+// PURPOSE: MAX31855 - Thermocouple
+//    DATE: 2014-01-01
+//     URL:
+//
+// Released to the public domain
+//
+
+#if (ARDUINO < 100)
+#include "WProgram.h"
+#else
+#include "Arduino.h"
+#endif
+
+#define MAX31855_VERSION "0.1.00"
+
+#define STATUS_OK               0x00
+#define STATUS_OPEN_CIRCUIT     0x01
+#define STATUS_SHORT_TO_GND     0x02
+#define STATUS_SHORT_TO_VCC     0x04
+
+class MAX31855 
+{
+public:
+    MAX31855(uint8_t SCLK, uint8_t CS, uint8_t MISO);
+    void begin();
+    uint8_t read();
+    float getInternal(void) { return _internal; };
+    // Celsius
+    float getTemperature(void) { return _temperature; } ;
+    uint8_t getStatus(void) {return _status; } ;
+
+private:
+    uint32_t _read();
+    float _internal;
+    float _temperature;
+    uint8_t _status;
+    
+    uint8_t _sclk;
+    uint8_t _miso;
+    uint8_t _cs;
+};
+
+#endif

libraries/MAX31855/examples/max31855_demo0/max31855_demo0.ino

@@ -0,0 +1,46 @@
+//
+//    FILE: max31855_demo.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.01
+// PURPOSE: thermocouple lib demo application
+//    DATE: 2014-01-01
+//     URL:
+//
+// Released to the public domain
+//
+
+#include "MAX31855.h"
+
+const int doPin = 7;
+const int csPin = 6;
+const int clPin = 5;
+
+MAX31855 tc(clPin, csPin, doPin);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.print("Start max31855_demo: ");
+  Serial.println(MAX31855_VERSION);
+  Serial.println();
+
+  tc.begin();
+}
+
+void loop() 
+{
+  int status = tc.read();
+  Serial.print("stat:\t\t");
+  Serial.println(status);
+
+  float internal = tc.getInternal();
+  Serial.print("internal:\t");
+  Serial.println(internal);
+
+  float temp = tc.getTemperature();
+  Serial.print("temperature:\t");
+  Serial.println(temp);
+  delay(1000);
+}
+
+

libraries/MAX31855/examples/max31855_demo1/max31855_demo1.ino

@@ -0,0 +1,48 @@
+//
+//    FILE: max31855_demo1.ino
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.01
+// PURPOSE: thermocouple lib demo application
+//    DATE: 2014-01-02
+//     URL:
+//
+// Released to the public domain
+//
+
+#include "MAX31855.h"
+
+const int doPin = 7;
+const int csPin = 6;
+const int clPin = 5;
+
+MAX31855 tc(clPin, csPin, doPin);
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.print("Start max31855_demo: ");
+  Serial.println(MAX31855_VERSION);
+  Serial.println();
+
+  tc.begin();
+}
+
+void loop() 
+{
+  int status = tc.read();
+  if (status != 0)
+  {
+    Serial.print("stat:\t\t");
+    Serial.println(status);
+  }
+
+  float temp = tc.getTemperature();
+  int m = temp*10 - 200;
+  Serial.print(temp);
+  Serial.print('\t');
+  for (int i=0; i< m; i++) Serial.write(']');
+  Serial.println();
+}
+
+
+

libraries/MAX31855/readme.txt

@@ -0,0 +1,34 @@
+
+Working is as follows:
+
+first is to instantiate a constructor:
+
+#include "MAX31855.h"
+
+const int doPin = 7;
+const int csPin = 6;
+const int clPin = 5;
+
+MAX31855 tc(clPin, csPin, doPin);
+
+
+To get a reading one must call tc.read() 
+
+This is the workhorse, it returns the status of the last read which is 0..7
+0 = OK
+bit 0 set = thermocouple open circuit
+bit 1 set = thermocouple short to GND
+bit 2 set = thermocouple short to VCC
+
+
+After a tc.read() you can do tc.getTemperature() and tc.getInternal().
+repeated getTemperature() will give the same value until a new tc.read();
+
+The reason for this is that it allows the object holds its last known temperature.
+Now one can do:
+
+float last = tc.getTemperature();
+tc.read();
+float new = tc.getTemperature();
+float delta = new - last;
+