Removing wire.begin from lib. Adding position accuracy function.

Author: nseidle

src/SparkFun_Ublox_Arduino_Library.cpp

@@ -41,7 +41,11 @@ void SFE_UBLOX_GPS::begin(TwoWire &wirePort)
 
 	//We expect caller to begin their I2C port, with the speed of their choice external to the library
 	//But if they forget, we start the hardware here.
-	_i2cPort->begin();
+	
+	//We're moving away from the practice of starting Wire hardware in a library. This is to avoid cross platform issues. 
+	//ie, there are some platforms that don't handle multiple starts to the wire hardware. Also, every time you start the wire
+	//hardware the clock speed reverts back to 100kHz regardless of previous Wire.setClocks().
+	//_i2cPort->begin();
 
 	setI2CReadAddress(0x42); //By default, use 0x42
 }
@@ -475,6 +479,30 @@ boolean SFE_UBLOX_GPS::waitForResponse(uint16_t maxTime)
 }
 
 
+//Get the current 3D high precision positional accuracy - a fun thing to watch
+//Returns a float representing the 3D accuracy in millimeters
+uint32_t SFE_UBLOX_GPS::getPositionAccuracy(uint16_t maxWait)
+{
+  packetCfg.cls = UBX_CLASS_NAV;
+  packetCfg.id = UBX_NAV_HPPOSECEF;
+  packetCfg.len = 0;
+
+  if(sendCommand(packetCfg, maxWait) == false)
+    return(0); //If command send fails then bail
+
+  //We got a response, now parse the bits into the float variable
+  uint32_t tempAccuracy = 0;
+  tempAccuracy |= payloadCfg[24] << 8*0;
+  tempAccuracy |= payloadCfg[25] << 8*1;
+  tempAccuracy |= payloadCfg[26] << 8*2;
+  tempAccuracy |= payloadCfg[27] << 8*3;
+
+  if(tempAccuracy % 10) >= 5) tempAccuracy += 5; //Round fraction of mm up to next mm if .5 or above
+  tempAccuracy /= 10; //Convert 0.1mm units to mm
+
+  return(tempAccuracy);
+}
+
 //Get the current TimeMode3 settings - these contain survey in statuses
 boolean SFE_UBLOX_GPS::getSurveyMode(uint16_t maxWait)
 {

src/SparkFun_Ublox_Arduino_Library.h

@@ -85,14 +85,15 @@ const uint8_t UBX_CLASS_LOG = 0x21;
 const uint8_t UBX_CLASS_SEC = 0x27;
 const uint8_t UBX_CLASS_HNR = 0x28;
 
-const uint8_t UBX_CFG_PRT = 0x00;
-const uint8_t UBX_CFG_RATE = 0x08;
+const uint8_t UBX_CFG_PRT = 0x00; //Used to configure port specifics
+const uint8_t UBX_CFG_RATE = 0x08; //Used to set port baud rates
 
 const uint8_t UBX_CFG_TMODE3 = 0x71; //Used to enable Survey In Mode
 const uint8_t SVIN_MODE_DISABLE = 0x00;
 const uint8_t SVIN_MODE_ENABLE = 0x01;
 
 const uint8_t UBX_NAV_SVIN = 0x3B; //Used for checking Survey In status
+const uint8_t UBX_NAV_HPPOSECEF = 0x13; //Find our positional accuracy (high precision)
 
 //The following are used to enable RTCM messages
 const uint8_t UBX_CFG_MSG = 0x01;
@@ -132,7 +133,7 @@ class SFE_UBLOX_GPS
     SFE_UBLOX_GPS(void);
 
     //By default use the default I2C address, and use Wire port
-    void begin(TwoWire &wirePort);
+    void begin(TwoWire &wirePort = Wire);
 
 	boolean isConnected(); //Returns turn if device answers on _gpsI2Caddress address
 
@@ -167,6 +168,8 @@ class SFE_UBLOX_GPS
 	boolean setRTCMport(uint8_t portID, boolean enableRTCM3, uint16_t maxWait = 250); //Enable/Disable RTCM3 (both input and output) for a given port
 
 	boolean getPortSettings(uint8_t portID, uint16_t maxWait = 250); //Returns the current protocol bits in the UBX-CFG-PRT command for a given port
+	
+	uint32_t getPositionAccuracy(uint16_t maxWait = 500); //Returns the 3D accuracy of the current high-precision fix
 
 	struct svinStructure {
 		boolean active;
@@ -176,7 +179,7 @@ class SFE_UBLOX_GPS
 	} svin;
 
 	uint16_t rtcmFrameCounter = 0;
-
+	
   private:
 
 	//Depending on the sentence type the processor will load characters into different arrays