device

R2026b

Connection to device on I2C bus on Arduino or ESP32 hardware

Description

Add-On Required: This feature requires the MATLAB Support Package for Arduino Hardware add-on.

This object represents a connection to the I2C device on Arduino^® or ESP32 hardware. Attach an I2C device to the appropriate pins on the Arduino or ESP32 hardware. You can interact with the I2C device using the functions listed in Object Functions.

Creation

Syntax

deviceObj = device(arduinoObj,'I2CAddress',I2CAddress,Name=Value)

Description

deviceObj = device(arduinoObj,'I2CAddress',I2CAddress,Name=Value) creates an object that represents the connection between an I2C peripheral connected to the central Arduino or ESP32 hardware. The Arduino or ESP32 hardware is represented by an arduino object. You can also customize the connection further using one or more name-value arguments. The 'I2CAddress' name-value argument is mandatory for creating the I2C device connection.

Input Arguments

arduinoObj — Arduino or ESP32 hardware connection

arduino object

Arduino or ESP32 hardware connection created using arduino, specified as an arduino object.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: deviceObj = device(arduinoObj,'I2CAddress','0x71');

I2CAddress — Address of I2C device

character vector | string | integer scalar | hexadecimal | binary

This is a mandatory name value pair argument if you are connecting to an I2C device. Address of the I2C device connected to the I2C bus, specified as a character vector, string, or integer. The address can be a hex or a scalar integer. Obtain this address value using the scanI2CBus function.

Example: deviceObj = device(arduinoObj,'I2CAddress','0x68')

Bus — I2C bus number

0 (default) | 1

I2C bus number, specified as 0 or 1. The default value is 0.

Note

Bus number 1 is only available on Due and Nano33BLE boards. Other Arduino boards support Bus number 0.

Example: deviceObj = device(arduinoObj,'I2CAddress','0x61',Bus=0) creates a connection to the I2C bus on the hardware.

BitRate — Maximum speed of I2C communication

100000 (default) | 400000

The maximum speed of I2C communication in bits/s, specified as 100000 or 400000 bits/s.

Example: deviceObj = device(arduinoObj,'I2CAddress','0x71',BitRate=100000) creates a connection to the I2C device and sets the bitrate to 100000 bits/s.

Data Types: double

Properties

Interface — Type of interface used for communication

Read-only: 'I2C'

This property is read-only.

Specifies the type of interface used for communication.

Example:

>> deviceObj.Interface
ans = 
      I2C

I2CAddress — Address of I2C device

Read-only: numeric

This property is read-only.

I2C device address on the Arduino hardware, specified as a number.

Example:

>> deviceObj.I2CAddress
ans = 
      104 

Data Types: double

Bus — I2C bus number

Read-only: 0 (default) | 1

This property is read-only.

I2C bus number, specified as 0 or 1. The default value is 0.

Note

Only Arduino Due board supports both the I2C bus numbers 0 and 1.

Example:

>> deviceObj.Bus
ans = 
      0 

Data Types: double

SCLPin — Serial clock pin

Read-only: character vector

This property is read-only.

This property is read-only. A serial clock pin for the serial clock signal that the I2C central generates.

Note

SCLPin for I2CBus1 appears as SCL1.

Example:

>> deviceObj.SCLPin
ans = 
      'A5' 

Data Types: char

SDAPin — Serial data pin

character vector

This property is read-only. A serial data pin for a serial data signal.

Note

SDAPin for I2CBus1 appears as SDA1.

Example:

>> deviceObj.SDAPin
ans = 
      'A4' 

Data Types: char

BitRate — Speed at which bus is set for I2C communication

Read-only: 100000 | positive integer

This property is read-only.

The speed at which bus is set for I2C communication, specified as a positive integer in bits/s.

Example:

>> deviceObj.BitRate
ans = 
      100000

Data Types: double

Object Functions

read	Read data from I2C bus
readRegister	Read data from I2C device register
write	Write data to I2C bus
writeRegister	Write data to I2C device registers

Examples

Create I2C Device Connection

Create an arduino object with the I2C library.

arduinoObj = arduino("COM15","Uno",Libraries="I2C")

arduinoObj = 
  arduino with properties:

                  Port: 'COM15'
                 Board: 'Uno'
         AvailablePins: {'D2-D13', 'A0-A5'}
  AvailableDigitalPins: {'D2-D13', 'A0-A5'}
      AvailablePWMPins: {'D3', 'D5-D6', 'D9-D11'}
   AvailableAnalogPins: {'A0-A5'}
    AvailableI2CBusIDs: [0]
             Libraries: {'I2C'}
Show all properties

Create a device object.

deviceObj = device(arduinoObj,I2CAddress=0x50)

deviceObj = 
  device with properties:

             Interface: 'I2C'
            I2CAddress: 80 ('0x50')
                   Bus: 0
                SCLPin: 'A5'
                SDAPin: 'A4'
               BitRate: 100000 (bits/s)

Show functions

More About

Code Generation Using MATLAB Function Block

• Use device in a MATLAB^® Function block with the Simulink^® Support Package for Arduino Hardware to generate code that can be deployed on Arduino Hardware.

• Specifying BitRate as a name value pair argument is not supported the in MATLAB Function block. You can set BitRate from the Configuration Parameters dialog box. To set the BitRate:

  • On the Simulink Toolstrip, in the Hardware tab, click Hardware Settings to open the Configuration Parameters dialog box.

  • In the Configuration Parameters dialog box, select Hardware Implementation. Verify that the Hardware board parameter is set to the appropriate Arduino board.

  • Go to Hardware board settings > Target hardware resources > I2C properties.

  • Enter the value to set BitRate in I2C Bus Speed(Hz).

• The properties Interface, BitRate, SCLPin, and SDAPin are not accessible from the device object.

Alternative Functionality

App

Use Arduino Explorer to configure the I2C peripheral and read from and write to I2C peripherals connected to Arduino or any other supported hardware. You can use the app in the installed version of MATLAB and MATLAB Online™. For more information, see Connect to I2C Device Using Arduino Explorer App.

Version History

Introduced in R2019a