I2C_device_Arduino

An I²C utility class for Arduino

What is this?

An Arduino library for I²C device operations.
This is an abstraction class which can be used for all I²C devices to manage access at the register level.

In addition to the device abstraction, it provides ping() and scan() as class methods.

See test_LM75B.cpp and test_LM75B.h as a sample for how a sub-class can be derived to make an actual device-supporting class.

Document

Details of the library are provided in this document.

Example

An example code is available using test_LM75B class which is included in this library distribution.
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 every second.

Using different I²C bus

For normal usage of an I²C device which is derived from I2C_device class, it will be like the sample below. This is intended to use the Wire instance of Arduino SDK to access I2C, implicitly.
(Using test_LM75B class included in this library package.)

#include <I2C_device.h>
#include <test_LM75B.h>  //  <-- test_LM75B is just for testing purpose
 
test_LM75B sensor(Wire);
 
void setup() {
  Serial.begin(9600);
  while (!Serial)
    ;
 
  Serial.println("\r***** Hello, I2C_device! *****");
 
  Wire.begin();
 
  I2C_device::scan();
}
 
void loop() {
  Serial.println(sensor.read());
  delay(1000);
}

If a user needs to use other instances of TwoWire class (a class for Wire), it could be done like below.
In this sample, the I²C device is connected to Wire1 (It's SDA1&SCL1 pins on Arduino DUE). Wire1 should be used explicitly.

#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() {
  Serial.begin(9600);
  while (!Serial)
    ;
 
  Serial.println("\r***** Hello, I2C_device! *****");
 
  // Wire.begin();  //  Changed to next line
  Wire1.begin();
 
  I2C_device::scan(Wire1, 124); //  Scan stop at 124
}
 
void loop() {
  Serial.println(sensor.read());
  delay(1000);
}

TIPS

For a 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 the type of target board and uses the right instance for the target.

#include <I2C_device.h>
#include <test_LM75B.h>  //  <-- test_LM75B is just for testing purpose
 
#if defined( ARDUINO_AVR_UNO ) // for Arduino UNO R3
  TwoWire& w = Wire;
  const String s = "Code is compiled for Arduino UNO R3 to use \"Wire\" instance";
#elif defined( ARDUINO_UNOR4_MINIMA ) || defined( ARDUINO_UNOR4_WIFI ) // for Arduino UNO R4
  TwoWire& w = Wire;
  const String s = "Code is compiled for Arduino UNO R4 to use \"Wire\" instance";
#elif defined( ARDUINO_SAM_DUE ) // for Arduino Due
  TwoWire& w = Wire1;
  const String s = "Code is compiled for Arduino DUE to use \"Wire1\" instance";
#else
  #error "not supported board"
#endif
 
test_LM75B sensor(w);
 
void setup() {
  Serial.begin(9600);
  while (!Serial)
    ;
 
  Serial.println("\r***** Hello, I2C_device! *****");
  Serial.println(s);
 
  w.begin();
 
  I2C_device::scan(w, 124);  //  Scan stop at 124
}
 
void loop() {
  Serial.println(sensor.read());
  delay(1000);
}

References

Related libraries

Library	Feature	Target devices	Required library
GPIO_NXP_Arduino	GPIO libraries	PCAL6408A, PCAL6416A, PCAL6524, PCAL6534, PCA9555, PCA9554	I2C_device_Arduino
LCDDriver_NXP_Arduino	LCD driver libraries	PCA8561	I2C_device_Arduino
LEDDriver_NXP_Arduino	LED driver libraries	PCA9955B, PCA9956B, PCA9957	I2C_device_Arduino
MUX_SW_NXP_Arduino	I²C mux/switch libraries	PCA9846	I2C_device_Arduino
RTC_NXP_Arduino	RTC libraries	PCF2131, PCF85063A	I2C_device_Arduino
TempSensor_NXP_Arduino	Temperature sensor libraries	LM75B, PCT2075, P3T1085	I2C_device_Arduino
I2C_device_Arduino	Base library for I²C operations	none (can be applied as base class for all I²C targets)	—