Change how we readTemperature(). Updated Temp Sense example.

Fix for issue 19.

Author: nseidle

examples/Example3_Temperature_Sense/Example3_Temperature_Sense.ino

@@ -19,19 +19,17 @@
 */
 
 #include <Wire.h>
-#include "MAX30105.h"
-
-#include "heartRate.h"
 
+#include "MAX30105.h"  //Get it here: http://librarymanager/All#SparkFun_MAX30105
 MAX30105 particleSensor;
 
 void setup()
 {
-  Serial.begin(115200);
+  Serial.begin(9600);
   Serial.println("Initializing...");
 
   // Initialize sensor
-  if (!particleSensor.begin(Wire, I2C_SPEED_FAST)) //Use default I2C port, 400kHz speed
+  if (particleSensor.begin(Wire, I2C_SPEED_FAST) == false) //Use default I2C port, 400kHz speed
   {
     Serial.println("MAX30105 was not found. Please check wiring/power. ");
     while (1);
@@ -41,6 +39,8 @@ void setup()
   //you may want to turn off the LEDs to avoid any local heating
   particleSensor.setup(0); //Configure sensor. Turn off LEDs
   //particleSensor.setup(); //Configure sensor. Use 25mA for LED drive
+
+  particleSensor.enableDIETEMPRDY(); //Enable the temp ready interrupt. This is required.
 }
 
 void loop()

src/MAX30105.cpp

@@ -158,7 +158,7 @@ boolean MAX30105::begin(TwoWire &wirePort, uint32_t i2cSpeed, uint8_t i2caddr) {
 
   // Populate revision ID
   readRevisionID();
-
+  
   return true;
 }
 
@@ -364,6 +364,10 @@ uint8_t MAX30105::getReadPointer(void) {
 // Die Temperature
 // Returns temp in C
 float MAX30105::readTemperature() {
+	
+  //DIE_TEMP_RDY interrupt must be enabled
+  //See issue 19: https://github.com/sparkfun/SparkFun_MAX3010x_Sensor_Library/issues/19
+  
   // Step 1: Config die temperature register to take 1 temperature sample
   writeRegister8(_i2caddr, MAX30105_DIETEMPCONFIG, 0x01);
 
@@ -372,16 +376,20 @@ float MAX30105::readTemperature() {
   unsigned long startTime = millis();
   while (millis() - startTime < 100)
   {
-    uint8_t response = readRegister8(_i2caddr, MAX30105_DIETEMPCONFIG);
-    if ((response & 0x01) == 0) break; //We're done!
+    //uint8_t response = readRegister8(_i2caddr, MAX30105_DIETEMPCONFIG); //Original way
+    //if ((response & 0x01) == 0) break; //We're done!
+    
+	//Check to see if DIE_TEMP_RDY interrupt is set
+	uint8_t response = readRegister8(_i2caddr, MAX30105_INTSTAT2);
+    if ((response & MAX30105_INT_DIE_TEMP_RDY_ENABLE) > 0) break; //We're done!
     delay(1); //Let's not over burden the I2C bus
   }
   //TODO How do we want to fail? With what type of error?
   //? if(millis() - startTime >= 100) return(-999.0);
 
   // Step 2: Read die temperature register (integer)
   int8_t tempInt = readRegister8(_i2caddr, MAX30105_DIETEMPINT);
-  uint8_t tempFrac = readRegister8(_i2caddr, MAX30105_DIETEMPFRAC);
+  uint8_t tempFrac = readRegister8(_i2caddr, MAX30105_DIETEMPFRAC); //Causes the clearing of the DIE_TEMP_RDY interrupt
 
   // Step 3: Calculate temperature (datasheet pg. 23)
   return (float)tempInt + ((float)tempFrac * 0.0625);