Adjusted the state machine to read the temperature less often (from twice a second to every 4 seconds). Added a small smoothing filter.

git-svn-id: https://arducopter.googlecode.com/svn/trunk@2552 f9c3cf11-9bcb-44bc-f272-b75c42450872

libraries/APM_BMP085/APM_BMP085.cpp

@@ -55,12 +55,13 @@ APM_BMP085_Class::APM_BMP085_Class()
 void APM_BMP085_Class::Init(int initialiseWireLib)
 {
 	byte buff[22];
-  int i=0;
+	int i = 0;
 
-  pinMode(BMP085_EOC,INPUT);   // End Of Conversion (PC7) input
+	pinMode(BMP085_EOC, INPUT);	 // End Of Conversion (PC7) input
 
 	if( initialiseWireLib != 0 )
 			Wire.begin();
+
 	oss = 3;					 // Over Sampling setting 3 = High resolution
 	BMP085_State = 0;		 // Initial state
 
@@ -70,12 +71,13 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
 	Wire.endTransmission();
 
 	Wire.requestFrom(BMP085_ADDRESS, 22);
+
   //Wire.endTransmission();
-  while(Wire.available())
-  { 
+	while(Wire.available()){
 		buff[i] = Wire.receive();	// receive one byte
 		i++;
 	}
+
 	ac1 = ((int)buff[0] << 8) | buff[1];
 	ac2 = ((int)buff[2] << 8) | buff[3];
 	ac3 = ((int)buff[4] << 8) | buff[5];
@@ -90,7 +92,7 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
 
   //Send a command to read Temp
 	Command_ReadTemp();
-  BMP085_State=1;
+	BMP085_State = 1;
 }
 
 
@@ -98,39 +100,31 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
 // We read one time Temperature (state=1) and then 4 times Pressure (states 2-5)
 uint8_t APM_BMP085_Class::Read()
 {
-uint8_t result=0;
+	uint8_t result = 0;
 
-	if (BMP085_State==1)
-	{
-		if (digitalRead(BMP085_EOC))
-		{
+	if (BMP085_State == 1){
+		if (digitalRead(BMP085_EOC)){
 			ReadTemp();						 // On state 1 we read temp
 			BMP085_State++;
 			Command_ReadPress();
 		}
-	}
-	else
-	{
-		if (BMP085_State==5)
-		{
-			if (digitalRead(BMP085_EOC))
-			{
+	}else{
+		if (BMP085_State == 40){
+			if (digitalRead(BMP085_EOC)){
 				ReadPress();
 				Calculate();
-				BMP085_State = 1;    // Start again from state=1
+
+				BMP085_State = 1;			// Start again from state = 1
 				Command_ReadTemp();			// Read Temp
-				result=1;            // New pressure reading
+				result = 1;					// New pressure reading
 			}
-		}
-		else
-		{
-			if (digitalRead(BMP085_EOC))
-			{
+		}else{
+			if (digitalRead(BMP085_EOC)){
 				ReadPress();
 				Calculate();
 				BMP085_State++;
 				Command_ReadPress();
-				result=1;            // New pressure reading
+				result = 1;					// New pressure reading
 			}
 		}
 	}
@@ -143,7 +137,7 @@ void APM_BMP085_Class::Command_ReadPress()
 {
 	Wire.beginTransmission(BMP085_ADDRESS);
 	Wire.send(0xF4);
-  Wire.send(0x34+(oss<<6));  //write_register(0xF4,0x34+(oversampling_setting<<6));
+	Wire.send(0x34+(oss << 6));	// write_register(0xF4, 0x34+(oversampling_setting << 6));
 	Wire.endTransmission();
 }
 
@@ -159,19 +153,25 @@ void APM_BMP085_Class::ReadPress()
 	Wire.endTransmission();
 
 	Wire.requestFrom(BMP085_ADDRESS, 3); // read a byte
+
 	while(!Wire.available()) {
     // waiting
 	}
+
 	msb = Wire.receive();
+
 	while(!Wire.available()) {
     // waiting
 	}
+
 	lsb = Wire.receive();
+
 	while(!Wire.available()) {
     // waiting
 	}
+
 	xlsb = Wire.receive();
-  RawPress = (((long)msb<<16) | ((long)lsb<<8) | ((long)xlsb)) >> (8-oss);
+	RawPress = (((long)msb << 16) | ((long)lsb << 8) | ((long)xlsb)) >> (8 - oss);
 }
 
 // Send Command to Read Temperature
@@ -187,18 +187,20 @@ void APM_BMP085_Class::Command_ReadTemp()
 void APM_BMP085_Class::ReadTemp()
 {
 	byte tmp;
+	int16_t tmp2;
 
 	Wire.beginTransmission(BMP085_ADDRESS);
 	Wire.send(0xF6);
 	Wire.endTransmission();
 
 	Wire.beginTransmission(BMP085_ADDRESS);
-  Wire.requestFrom(BMP085_ADDRESS,2);
+	Wire.requestFrom(BMP085_ADDRESS, 2);
 	while(!Wire.available());	// wait
-  RawTemp = Wire.receive();
+	tmp2 = Wire.receive();
 	while(!Wire.available());	// wait
 	tmp = Wire.receive();
-  RawTemp = RawTemp<<8 | tmp;
+	RawTemp += tmp2 << 8 | tmp;
+	RawTemp = RawTemp >> 1;
 }
 
 // Calculate Temperature and Pressure in real units.
@@ -252,26 +254,21 @@ void APM_BMP085_HIL_Class::Init(int initialiseWireLib)
 
 
 // Read the sensor. This is a state machine
-// We read one time Temperature (state=1) and then 4 times Pressure (states 2-5)
+// We read one time Temperature (state = 1) and then 4 times Pressure (states 2-5)
 uint8_t APM_BMP085_HIL_Class::Read()
 {
-    uint8_t result=0;
+	uint8_t result = 0;
 
-	if (BMP085_State==1)
-	{
+	if (BMP085_State == 1){
 		BMP085_State++;
-	}
-	else
-	{
-		if (BMP085_State==5)
-		{
-            BMP085_State = 1;    // Start again from state=1
-            result=1;            // New pressure reading
-		}
-		else
-		{
+	}else{
+
+		if (BMP085_State == 5){
+			BMP085_State = 1;				// Start again from state = 1
+			result = 1;						// New pressure reading
+		}else{
 			BMP085_State++;
-            result=1;            // New pressure reading
+			result = 1;						// New pressure reading
 		}
 	}
 	return(result);

libraries/APM_BMP085/APM_BMP085.h

@@ -15,6 +15,7 @@ class APM_BMP085_Class
 	void ReadPress();
 	void ReadTemp();
 	void Calculate();
+
   public:
 	int32_t RawPress;
 	int32_t RawTemp;