enableI2C

Enable I2C interface

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

Syntax

enableI2C(bbb, bus_number)

Description

enableI2C(bbb, bus_number) enables the indicated I2C bus and configures the GPIO pins for use as I2C pins. After you start the hardware, the i2c-1 bus is enabled by default.

Examples

Enable, Connect, and Exchange Data with I2C Device

You can connect and exchange data with an I2C device on I2C bus 1.

Create a connection from the MATLAB^® software to the BeagleBone^® Black hardware.

bbb = beaglebone

bbb = 

  beaglebone with properties:

           DeviceAddress: '192.168.7.2'
               BoardName: 'BeagleBone Black Rev 00C0'
           AvailableLEDs: {'USR0'  'USR1'  'USR2'  'USR3'}
    AvailableDigitalPins: {1x29 cell}
     AvailableAnalogPins: {'AIN0'  'AIN1'  'AIN2'  'AIN3'  'AIN4'  'AIN5'  'AIN6'}
        AvailablePWMPins: {}
    AvailableSPIChannels: {}
       AvailableI2CBuses: {'i2c-1'}
    AvailableSerialPorts: {}
        AvailableWebcams: {} 

Enable I2C bus 1.

enableI2C(bbb,1)

Display AvailableI2CBuses.

bbb.AvailableI2CBuses

ans = 

    'i2c-1'    'i2c-2'

AvailableI2CBuses displays default bus 2 as i2c-1. The 1 is an internal index number. When you enable bus 1, AvailableI2CBuses displays it as i2c-2.

After physically connecting your I2C device to the I2C bus 1 pins, get the addresses of two I2C devices attached to I2C bus 1.

scanI2CBus(bbb,'i2c-2')

ans = 

     {'0x55','0x20'}

Create a connection, i2csensor, from the MATLAB software to the I2C sensor at '0x20'.

i2csensor = i2cdev(bbb,'i2c-2','0x20')

i2csensor = 

I2C with Properties:
     Bus: i2c-2
    I2CAddress: 0x20
       TimeOut: 10

Read two uint8 numbers from the sensor.

output1 = read(i2csensor,2);

Read the value of register 14 from the sensor.

output2 = readRegister(i2csensor,14);

Create a connection, i2cdisplay, from the MATLAB software to an I2C LED display at '0x55'.

i2cdisplay = i2cdev(bbb,'i2c-2','0x55')

i2cdisplay = 

I2C with Properties:
     Bus: i2c-2
    I2CAddress: 0x55
       TimeOut: 10

Write characters to the display.

write(i2cdisplay,[hex2dec('20') hex2dec('51')])

Write a scalar hexadecimal value, hex2dec('08'), to register 3 on an I2C device. uint8 is the default data type.

writeRegister(i2cdisplay,3,hex2dec('08'))

Input Arguments

bbb — Connection to BeagleBone Black hardware

beaglebone object

BeagleBone Black connection created using beaglebone, specified as an object.

bus_number — Reference to specific I2C bus

2 (default) | 1

The bus number identifies the I2C bus being enabled. By default, bus 2 is always enabled.

AvailableI2CBuses displays default bus 2 as i2c-1. The 1 is an index number. When you enable bus 1, AvailableI2CBuses displays it as i2c-2.

I2C bus 1 shares pins with SPI bus 0.

Example: 1

Version History

Introduced in R2015a