I2C Switch Node JS Library

Node.js Library to use with the 4-channel I2C Switch.

Install

To download to your Raspberry Pi type in the terminal:

git clone https://github.com/abelectronicsuk/ABElectronics_NodeJS_Libraries.git

The I2C Switch library is located in the /lib/i2cswitch/ directory

The example files are located in the /examples/i2cswitch/ directory

The I2C Switch library requires the i2c-bus and rpio libraries to run.

Install i2c-bus from npm package repository i2c-bus with

npm install i2c-bus

Install rpio from npm package repository rpio with

npm install rpio

I2CSwitch Class

The I2CSwitch class contains the functions needed to control the channel state and reset the PCA9546A controller used on the I2C Switch.

I2CSwitch(address) 

Parameter: address - 0x70 to 0x77. I2C address for the target device

Functions:

switchChannel(channel) 

Enable the switch on the selected channel and disable all other channels
Parameter: channel - 1 to 4
Returns: null

setChannelState(channel, state) 

Set the output on single channels
Parameter: channel - 1 to 4,
Parameter: true = channel enabled, false = channel disabled
Returns: null

getChannelState(channel) 

Get the state of the specified channel
Parameter: channel - 1 to 4,
Returns: true = channel enabled, false = channel disabled

reset() 

Reset the I2C switch.
Resetting allows the switch to recover from a situation in which one of the downstream I2C buses is stuck in a low state. All channels will be set to an off-state.
Returns: null

Usage

To use the I2C Switch library in your code you must first import the library:

var i2cswitch = require('../../lib/i2cswitch/i2cswitch');

Next, you must initialise the I2CSwitch object:

var switchobject = new I2CSwitch(0x70);

Set the switch to channel 4

switchobject.switchChannel(4);

Get the status of the selected channel and print it to the console

var result = switchobject.getChannelState(4)

if (result == true){
    console.log('Switched to channel 4')
}
else{
    console.log('Error switching to channel 4')
}