Fixes error when writing new address to the ultrasonic object forcing an unnecessary reload

* Updates example four to continue with reading distance at the changed address.

Author: edspark

examples/Example4_ChangeAddress/Example4_ChangeAddress.ino

@@ -66,6 +66,7 @@ void setup()
   // Call change address.....
   sfeTkError_t err =  myUltrasonic.changeAddress(newAddr);
 
+
   if(err)
   {
     while(1)
@@ -75,16 +76,28 @@ void setup()
       delay(1000);
     }
   }
-  delay(1000);
 
-  Serial.print("Load up example 1 with the new address at: ");
-  Serial.println(newAddr, HEX);
-  Serial.println("Freezing....");
-  while(1)
-    ;
+  Serial.println("Address changed successfully!");
+  Serial.println("Reading Distance at new address......");
+  delay(3000);
 
 }
 
 void loop()
 {
+  uint16_t distance = 0;
+  myUltrasonic.triggerAndRead(distance);
+
+  // Print measurement
+  Serial.print("Distance (mm): ");
+  Serial.println(distance);
+
+  //Serial.println("Distance (cm): "); 
+  //Serial.print((distance / 10.0), 2);         
+
+  //Serial.println("Distace (in): "); 
+  //Serial.print((distance / 25.4), 2);         
+
+  // Wait a bit
+  delay(100);
 }

src/sfeQwiicUltrasonic.cpp

@@ -86,8 +86,8 @@ sfeTkError_t sfeQwiicUltrasonic::changeAddress(uint8_t &address)
             return kSTkErrFail;
 
         // We want to shift the address left before we send it.
-        address <<= 1;
-        const uint8_t toWrite[2] = {kUltrasonicAddressChangeCommand, address};
+        uint8_t tempAddress = address << 1;
+        const uint8_t toWrite[2] = {kUltrasonicAddressChangeCommand, tempAddress};
 
         // Write the new address to the device
         err = _theBus->writeRegion(toWrite, numBytes);
@@ -99,13 +99,11 @@ sfeTkError_t sfeQwiicUltrasonic::changeAddress(uint8_t &address)
         return kSTkErrFail;
     }
 
+    _theBus->setAddress(address);
     // Check whether the write was successful
     if (err != kSTkErrOk)
         return err;
 
-    // Update the address in the bus
-    _theBus->setAddress(address);
-
     // Done!
     return kSTkErrOk;
 }