pyb.I2C.rst

class I2C -- a two-wire serial protocol

I2C is a two-wire protocol for communicating between devices. At the physical level it consists of 2 wires: SCL and SDA, the clock and data lines respectively.

I2C objects are created attached to a specific bus. They can be initialised when created, or initialised later on:

from pyb import I2C

i2c = I2C(1)                         # create on bus 1
i2c = I2C(1, I2C.MASTER)             # create and init as a master
i2c.init(I2C.MASTER, baudrate=20000) # init as a master
i2c.init(I2C.SLAVE, addr=0x42)       # init as a slave with given address
i2c.deinit()                         # turn off the peripheral

Printing the i2c object gives you information about its configuration.

Basic methods for slave are send and recv:

i2c.send('abc')      # send 3 bytes
i2c.send(0x42)       # send a single byte, given by the number
data = i2c.recv(3)   # receive 3 bytes

To receive inplace, first create a bytearray:

data = bytearray(3)  # create a buffer
i2c.recv(data)       # receive 3 bytes, writing them into data

You can specify a timeout (in ms):

i2c.send(b'123', timeout=2000)   # timout after 2 seconds

A master must specify the recipient's address:

i2c.init(I2C.MASTER)
i2c.send('123', 0x42)        # send 3 bytes to slave with address 0x42
i2c.send(b'456', addr=0x42)  # keyword for address

Master also has other methods:

i2c.is_ready(0x42)           # check if slave 0x42 is ready
i2c.scan()                   # scan for slaves on the bus, returning
                             #   a list of valid addresses
i2c.mem_read(3, 0x42, 2)     # read 3 bytes from memory of slave 0x42,
                             #   starting at address 2 in the slave
i2c.mem_write('abc', 0x42, 2, timeout=1000)

Constructors

Methods

Constants