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.
Printing the i2c object gives you information about its configuration.
The basic methods 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
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