more docs

Author: gigapod

docs/ar_ibus.md

@@ -43,3 +43,101 @@ The first implementation of the IBus interface is for the Arduino development en
 The results is outlined in the following class diagram:
 
 ![Device Class](images/sfetk_ibus_class.png)
+
+## sfeTkIBus Use
+
+The general steps when using the sfeTkIBus in device development are outlined in the following steps
+
+### Platform Independent/Bus Independent Driver
+
+Develop a platform independent version of a device driver that commutates using the sfeTkIBus interface. This driver should include a method to set the bus object, accepting a pointer to a sfeTkIBus interface/object. Actual bus setup is provided outside of the driver.
+
+This implementation would take the following form:
+
+```c++
+
+class myDriverClass
+{
+public:
+
+    myDriverClass(uint8_t address) : _addr{address}{}
+
+    bool begin()
+    {
+        // initialize things ...
+
+        return true;
+    }
+    void setCommunicationBus(sfeTkIBus *theBus)
+    {
+        _theBus = theBus;
+    }
+
+    bool updateDeviceData(uint8_t *data, size_t len)
+    {
+        if (!_theBus || !data || len == 0)
+            return false;
+
+        int status = _theBus->writeRegisterRegion(_addr, THE_REG, data, len);
+
+        return (status == 0);
+    }
+private:
+    sfeTkIBus *_theBus
+    uint8_t _addr;
+};
+```
+
+### Write a Platform Specific Driver, based on the core driver
+
+This driver sub-classes from the general/core driver class, builds and configures the desired bus object and passes this into the core driver.
+
+Basic concept - creating an I2C class in Arduino
+
+```c++
+
+class myArduinoDriveI2C : public myDriverClass
+{
+  public:
+    myArduinoDriverI2C() : myDriverClass(MY_DEFAULT_ADDRESS)
+    {}
+
+    bool begin()
+    {
+        if (!_theI2CBus.init())
+            return false;
+        setCommunicationBus(&_theI2CBus);
+
+        return myDriverClass::begin();
+    }
+
+private:
+   sfeTkBusI2C _theI2CBus;
+};
+```
+
+Basic concept - creating an SPI class in Arduino
+
+```c++
+
+class myArduinoDriveSPI : public myDriverClass
+{
+  public:
+    myArduinoDriverSPI() : myDriverClass(MY_DEFAULT_CS)
+    {}
+
+    bool begin()
+    {
+        SPISettings spiSettings = SPISettings(4000000, MSBFIRST, SPI_MODE3);
+
+        if (!_theSPIBus.init(SPI, spiSettings, true))
+            return false;
+        setCommunicationBus(&_theSPIBus);
+
+        return myDriverClass::begin();
+    }
+
+private:
+   sfeTkBusSPI _theSPIBus;
+};
+```