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pyb.I2C

Classes

I2C

Construct an I2C object on the given bus. bus can be 1 or 2, 'X' or

Module Contents

class pyb.I2C.I2C(bus, mode, baudrate=328125, *, prescaler=-1, polarity=1, phase=0, bits=8, firstbit=MSB, ti=False, crc=None)

Construct an I2C object on the given bus. bus can be 1 or 2, ‘X’ or ‘Y’. With no additional parameters, the I2C object is created but not initialised (it has the settings from the last initialisation of the bus, if any). If extra arguments are given, the bus is initialised. See init for parameters of initialisation.

The physical pins of the I2C buses on Pyboards V1.0 and V1.1 are:

I2C(1) is on the X position: (SCL, SDA) = (X9, X10) = (PB6, PB7)

I2C(2) is on the Y position: (SCL, SDA) = (Y9, Y10) = (PB10, PB11)

On the Pyboard Lite:

I2C(1) is on the X position: (SCL, SDA) = (X9, X10) = (PB6, PB7)

I2C(3) is on the Y position: (SCL, SDA) = (Y9, Y10) = (PA8, PB8)

Calling the constructor with ‘X’ or ‘Y’ enables portability between Pyboard types.

deinit() → None: Turn off the I2C bus.

init(mode, *, addr=18, baudrate=400000, gencall=False, dma=False) → None

Initialise the I2C bus with the given parameters:

mode must be either I2C.CONTROLLER or I2C.PERIPHERAL

addr is the 7-bit address (only sensible for a peripheral)

baudrate is the SCL clock rate (only sensible for a controller)

gencall is whether to support general call mode

dma is whether to allow the use of DMA for the I2C transfers (note that DMA transfers have more precise timing but currently do not handle bus errors properly)

The actual clock frequency may be lower than the requested frequency. This is dependent on the platform hardware. The actual rate may be determined by printing the I2C object.

is_ready(addr) → Incomplete: Check if an I2C device responds to the given address. Only valid when in controller mode.

mem_read(data, addr, memaddr, *, timeout=5000, addr_size=8) → Incomplete

Read from the memory of an I2C device:

data can be an integer (number of bytes to read) or a buffer to read into

addr is the I2C device address

memaddr is the memory location within the I2C device

timeout is the timeout in milliseconds to wait for the read

addr_size selects width of memaddr: 8 or 16 bits

Returns the read data. This is only valid in controller mode.

mem_write(data, addr, memaddr, *, timeout=5000, addr_size=8) → None

Write to the memory of an I2C device:

data can be an integer or a buffer to write from

addr is the I2C device address

memaddr is the memory location within the I2C device

timeout is the timeout in milliseconds to wait for the write

addr_size selects width of memaddr: 8 or 16 bits

Returns None. This is only valid in controller mode.

recv(recv, addr=0, *, timeout=5000) → bytes

Receive data on the bus:

recv can be an integer, which is the number of bytes to receive, or a mutable buffer, which will be filled with received bytes

addr is the address to receive from (only required in controller mode)

timeout is the timeout in milliseconds to wait for the receive

Return value: if recv is an integer then a new buffer of the bytes received, otherwise the same buffer that was passed in to recv.

scan() → List: Scan all I2C addresses from 0x01 to 0x7f and return a list of those that respond. Only valid when in controller mode.

send(send, addr=0, *, timeout=5000) → None

Send data on the bus:

send is the data to send (an integer to send, or a buffer object)

addr is the address to send to (only required in controller mode)

timeout is the timeout in milliseconds to wait for the send

Return value: None.

CONTROLLER: Incomplete: for initialising the bus to controller mode

PERIPHERAL: Incomplete: for initialising the bus to peripheral mode