To habdle generic TwoWire class instances other than only one "Wire" instance

Author: teddokano

README.md

@@ -18,6 +18,88 @@ It performs
 1. Scan of I²C bus. Result is shown as a table (executed by `I2C_device::scan()`)
 1. temperature reading from LM75B and its compatible device and showing result in every second. 
 
+## Using different I²C bus
+
+For normal usage of I²C device which is delived from I2C_device class, it will be like sample blelow. This intended to use `Wire` instance of Arduino SDK to access I2C, implicitly.  
+(Using test_LM75B class included in this library package.)
+```cpp
+#include <I2C_device.h>
+#include <test_LM75B.h>  //  <-- test_LM75B is just for testing purpose
+
+test_LM75B sensor;
+
+void setup() {
+  Wire.begin();
+  Serial.begin(9600);
+  Serial.println("\r***** Hello, I2C_device! *****");
+
+  I2C_device::scan();
+
+  float temp = sensor.read();
+}
+
+void loop() {
+  Serial.println(sensor.read());
+  delay(1000);
+}
+```
+
+If user need to use other instance of TwoWire class (a class for Wire), it could be done like below.  
+In this sample, the I²C device is connected Wire1 (It's SDA1&SCL1 pins on Arduino DUE). Wire1 should be used explisitly.  
+```cpp
+#include <I2C_device.h>
+#include <test_LM75B.h>  //  <-- test_LM75B is just for testing purpose
+
+//test_LM75B sensor;  //  Changed to next line
+test_LM75B sensor(Wire1);
+
+void setup() {
+  // Wire.begin();  //  Changed to next line
+  Wire1.begin();
+  Serial.begin(9600);
+  Serial.println("\r***** Hello, I2C_device! *****");
+
+  I2C_device::scan(Wire1, 124); //  Scan stop at 124
+}
+
+void loop() {
+  Serial.println(sensor.read());
+  delay(1000);
+}
+```
+
+### TIPS
+
+For more generic way to define the hardware, you can do it by compile option to detect the board and switch compile option.  
+In this sample, the compiler detects type of target board and use right instance for the target.  
+```cpp
+#include <I2C_device.h>
+#include <test_LM75B.h>  //  <-- test_LM75B is just for testing purpose
+
+#if defined( ARDUINO_AVR_UNO ) // for Arduino Uno
+TwoWire& w = Wire;
+#elif defined( ARDUINO_SAM_DUE ) // for Arduino Due
+TwoWire& w = Wire1;
+#else
+#error "not supported board"
+#endif
+
+test_LM75B sensor(w);
+
+void setup() {
+  w.begin();
+  Serial.begin(9600);
+  Serial.println("\r***** Hello, I2C_device! *****");
+
+  I2C_device::scan(w, 124);  //  Scan stop at 124
+}
+
+void loop() {
+  Serial.println(sensor.read());
+  delay(1000);
+}
+```
+
 # References
 
 ## Related libraries

docs/_i2_c__device_8cpp_source.html

@@ -78,8 +78,10 @@
 <table class="directory">
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#abd030d701ee101dbf359c05eddab50cf">bit_op16</a>(uint8_t reg, uint16_t mask, uint16_t value)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#a758abf4ad6fdca6d32c06ab7780b13b5">bit_op8</a>(uint8_t reg, uint8_t mask, uint8_t value)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
-  <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#ac1690942862f4dac204ff918b1f8ca48">i2c_addr</a></td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">private</span></td></tr>
-  <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#ad80b4138d2345ca258c9f33930853bc7">I2C_device</a>(uint8_t i2c_address, bool repeated_start_enable=true)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
+  <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a946e117192be1ed0499e509ca7e9482e">i2c</a></td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">private</span></td></tr>
+  <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#ac1690942862f4dac204ff918b1f8ca48">i2c_addr</a></td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">private</span></td></tr>
+  <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#ad80b4138d2345ca258c9f33930853bc7">I2C_device</a>(uint8_t i2c_address, bool repeated_start_enable=true)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
+  <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#ab8dae8d06ba97ffc06abc4c49c48d3b1">I2C_device</a>(TwoWire &amp;wire, uint8_t i2c_address, bool repeated_start_enable=true)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a2298c86cb79fdbb630a909c1ca970b05">ping</a>(void)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#a9827d0dd088d394df1d78e0e41573baf">ping</a>(uint8_t addr)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">static</span></td></tr>
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a9aa5aff32f1484d2282decfa0307c38d">read_r16</a>(uint8_t reg)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
@@ -91,7 +93,7 @@
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#aa7e393f9d636f9703047a96761828ade">repeated_start_enable</a>(bool en=true)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#a4b1c4e0952fc5c875ee845de98f2c35b">rs_dis</a></td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">private</span></td></tr>
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a371e31074e312ef7718ce71708f265c3">rx</a>(uint8_t *data, uint16_t size)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
-  <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#a7deb9cf0cc98d3382f172cd20d5d3bcd">scan</a>(void)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">static</span></td></tr>
+  <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#a8c95b5549c3ea77941e5c27783e9859a">scan</a>(TwoWire &amp;target_i2c=Wire, uint8_t stop=128)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"><span class="mlabel">static</span></td></tr>
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a7ffab6c133e8c3234d5f33f697632e93">tx</a>(uint8_t *data, uint16_t size, bool stop=true)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="odd"><td class="entry"><a class="el" href="class_i2_c__device.html#aa7db320551353b8d860221dc646f3989">write_r16</a>(uint8_t reg, uint16_t val)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>
   <tr class="even"><td class="entry"><a class="el" href="class_i2_c__device.html#a5f69560e9cb2d8ec33f2f5f8d497a34e">write_r8</a>(uint8_t reg, uint8_t val)</td><td class="entry"><a class="el" href="class_i2_c__device.html">I2C_device</a></td><td class="entry"></td></tr>