barometer: add purple_hardware option to Init()

this allows selection of right hardware at Init() time

libraries/APM_BMP085/APM_BMP085.cpp

@@ -33,6 +33,7 @@
 
 
 */
+
 extern "C" {
   // AVR LibC Includes
   #include <inttypes.h>
@@ -51,12 +52,21 @@ extern "C" {
 //{
 //}
 
+// the purple hardware needs to check the state of the
+// chip using a direct IO port
+// On Purple prerelease hw, the data ready port is hooked up to PE7, which
+// is not available to the arduino digitalRead function.
+#define BMP_DATA_READY() (_purple_hardware?(PINE&0x80):digitalRead(BMP085_EOC))
+
+
 // Public Methods //////////////////////////////////////////////////////////////
-void APM_BMP085_Class::Init(int initialiseWireLib)
+bool APM_BMP085_Class::Init(int initialiseWireLib, bool purple_hardware)
 {
 	byte buff[22];
 	int i = 0;
 
+	_purple_hardware = purple_hardware;
+
 	pinMode(BMP085_EOC, INPUT);	 // End Of Conversion (PC7) input
 
 	if( initialiseWireLib != 0 )
@@ -68,7 +78,9 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
   // We read the calibration data registers
 	Wire.beginTransmission(BMP085_ADDRESS);
 	Wire.send(0xAA);
-	Wire.endTransmission();
+	if (Wire.endTransmission() != 0) {
+		return false;
+	}
 
 	Wire.requestFrom(BMP085_ADDRESS, 22);
 
@@ -77,6 +89,9 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
 		buff[i] = Wire.receive();	// receive one byte
 		i++;
 	}
+	if (i != 22) {
+		return false;
+	}
 
 	ac1 = ((int)buff[0] << 8) | buff[1];
 	ac2 = ((int)buff[2] << 8) | buff[3];
@@ -93,6 +108,7 @@ void APM_BMP085_Class::Init(int initialiseWireLib)
   //Send a command to read Temp
 	Command_ReadTemp();
 	BMP085_State = 1;
+	return true;
 }
 
 /*
@@ -103,14 +119,14 @@ uint8_t APM_BMP085_Class::Read()
 	uint8_t result = 0;
 
 	if (BMP085_State == 1){
-		if (digitalRead(BMP085_EOC)){
+		if (BMP_DATA_READY()) {
 			ReadTemp();						 // On state 1 we read temp
 			BMP085_State++;
 			Command_ReadPress();
 		}
 	}else{
 		if (BMP085_State == 5){
-			if (digitalRead(BMP085_EOC)){
+			if (BMP_DATA_READY()){
 				ReadPress();
 				Calculate();
 
@@ -119,7 +135,7 @@ uint8_t APM_BMP085_Class::Read()
 				result = 1;					// New pressure reading
 			}
 		}else{
-			if (digitalRead(BMP085_EOC)){
+			if (BMP_DATA_READY()){
 				ReadPress();
 				Calculate();
 				BMP085_State++;
@@ -310,4 +326,4 @@ void APM_BMP085_Class::Calculate()
 	x1 = (x1 * 3038) >> 16;
 	x2 = (-7357 * p) >> 16;
 	Press = p + ((x1 + x2 + 3791) >> 4);
-}
+}

libraries/APM_BMP085/APM_BMP085.h

@@ -19,9 +19,10 @@ class APM_BMP085_Class
 	int32_t Press;
 	//int Altitude;
 	uint8_t oss;
+	bool _purple_hardware;
 	//int32_t Press0;  // Pressure at sea level
 
-	void Init(int initialiseWireLib = 1);
+	bool Init(int initialiseWireLib = 1, bool purple_hardware=false);
 	uint8_t Read();
 
   private:

libraries/APM_BMP085/APM_BMP085_hil.cpp

@@ -15,7 +15,7 @@ APM_BMP085_HIL_Class::APM_BMP085_HIL_Class()
 }
 
 // Public Methods //////////////////////////////////////////////////////////////
-void APM_BMP085_HIL_Class::Init(int initialiseWireLib)
+void APM_BMP085_HIL_Class::Init(int initialiseWireLib, bool purple_hardware)
 {
   BMP085_State=1;
 }

libraries/APM_BMP085/APM_BMP085_hil.h

@@ -13,7 +13,7 @@ class APM_BMP085_HIL_Class
 	int32_t Press;
 	//int Altitude;
 	uint8_t oss;
-	void Init(int initialiseWireLib = 1);
+	void Init(int initialiseWireLib = 1, bool purple_hardware=false);
 	uint8_t Read();
     void setHIL(float Temp, float Press);
 };

libraries/APM_BMP085/examples/APM_BMP085_test/APM_BMP085_test.pde

@@ -3,6 +3,7 @@
 	Code by Jordi MuÒoz and Jose Julio. DIYDrones.com
 */
 
+#include <FastSerial.h>
 #include <Wire.h>
 #include <APM_BMP085.h> // ArduPilot Mega BMP085 Library
 
@@ -10,12 +11,19 @@ APM_BMP085_Class APM_BMP085;
 
 unsigned long timer;
 
+FastSerialPort0(Serial);
+
+// set this to true on purple
+static bool purple_hardware = false;
+
 void setup()
 {	
 	Serial.begin(115200);
 	Serial.println("ArduPilot Mega BMP085 library test");
 	Serial.println("Initialising barometer..."); delay(100);
-	APM_BMP085.Init();	 // APM ADC initialization
+	if (!APM_BMP085.Init(1, purple_hardware)) {
+		Serial.println("Barometer initialisation FAILED\n");
+	}
 	Serial.println("initialisation complete."); delay(100);
 	delay(1000);
 	timer = millis();