smbus

go-smbus

Go bindings for the System Management Bus (SMBus) kernel interface This package provides simple bindings for the SMBus interfaces provided by the i2c-dev driver. I wrote this for the Raspberry Pi platform.

This code is largely untested. I'll happily accept a pull request for any bugs you might find

Installation

go get github.com/corrupt/go-smbus

Usage

Create an instance of SMBus using the factory method. It takes two parameters, the interface index and the bus address. The former is the enumerated device index. If your I2C device is /dev/i2c-1, your index is 1. The latter is the bus address to connect to from 0x00 to 0x77. It can later be changed using the Set_addr method.

smb, err := smbus.New(1, 0x68)
if err != nil {
    fmt.Println(err)              
    os.Exit(1)  
}

You can now use the SMBus API to write to and read from the bus. All methods evaluate errno and return a go error accordingly. Block read/write methods also return the number of read/written bytes.

cmd := 0xD0
val := 0x10
err := smb.Write_byte_data(cmd, val)

buf := make ([]byte, 4)
i, err := smb.Read_i2c_block_data(0xD1, buf)
if err != nil {
    fmt.Println(err)              
    //error handling
}
if i != len(buf) {
    //error handling
}

Changing the Bus Device

The SMBus type provides two convenience methods to close the existing device and optionally open a new one

smb.Bus_close()
smb.Bus_open(0x71)