Commit 1f1a03d0 authored by Damien George's avatar Damien George
Browse files

docs/library/machine.I2C: Deconditionalise all methods.

The cc3200 port is now similar enough to the standard machine.I2C API so
that all conditionals can be removed.
parent c49b2653
......@@ -9,86 +9,55 @@ 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.
.. only:: port_wipy
Printing the I2C object gives you information about its configuration.
Example::
Example usage::
from machine import I2C
from machine import I2C
i2c = I2C(0) # create on bus 0
i2c = I2C(0, I2C.MASTER) # create and init as a master
i2c.init(I2C.MASTER, baudrate=20000) # init as a master
i2c.deinit() # turn off the peripheral
i2c = I2C(freq=400000) # create I2C peripheral at frequency of 400kHz
# depending on the port, extra parameters may be required
# to select the peripheral and/or pins to use
Printing the i2c object gives you information about its configuration.
i2c.scan() # scan for slaves, returning a list of 7-bit addresses
.. only:: port_wipy
i2c.writeto(42, b'123') # write 3 bytes to slave with 7-bit address 42
i2c.readfrom(42, 4) # read 4 bytes from slave with 7-bit address 42
A master must specify the recipient's address::
i2c.init(I2C.MASTER)
i2c.writeto(0x42, '123') # send 3 bytes to slave with address 0x42
i2c.writeto(addr=0x42, b'456') # keyword for address
Master also has other methods::
i2c.scan() # scan for slaves on the bus, returning
# a list of valid addresses
i2c.readfrom_mem(0x42, 2, 3) # read 3 bytes from memory of slave 0x42,
# starting at address 2 in the slave
i2c.writeto_mem(0x42, 2, 'abc') # write 'abc' (3 bytes) to memory of slave 0x42
# starting at address 2 in the slave, timeout after 1 second
i2c.readfrom_mem(42, 8, 3) # read 3 bytes from memory of slave 42,
# starting at memory-address 8 in the slave
i2c.writeto_mem(42, 2, b'\x10') # write 1 byte to memory of slave 42
# starting at address 2 in the slave
Constructors
------------
.. only:: port_wipy
.. class:: I2C(bus, ...)
Construct an I2C object on the given bus. `bus` can only be 0.
If the bus is not given, the default one will be selected (0).
.. class:: I2C(id=-1, \*, scl, sda, freq=400000)
.. only:: not port_wipy
Construct and return a new I2C object using the following parameters:
.. class:: I2C(id=-1, \*, scl, sda, freq=400000)
Construct and return a new I2C object using the following parameters:
- `id` identifies the particular I2C peripheral. The default
value of -1 selects a software implementation of I2C which can
work (in most cases) with arbitrary pins for SCL and SDA.
If `id` is -1 then `scl` and `sda` must be specified. Other
allowed values for `id` depend on the particular port/board,
and specifying `scl` and `sda` may or may not be required or
allowed in this case.
- `scl` should be a pin object specifying the pin to use for SCL.
- `sda` should be a pin object specifying the pin to use for SDA.
- `freq` should be an integer which sets the maximum frequency
for SCL.
- `id` identifies the particular I2C peripheral. The default
value of -1 selects a software implementation of I2C which can
work (in most cases) with arbitrary pins for SCL and SDA.
If `id` is -1 then `scl` and `sda` must be specified. Other
allowed values for `id` depend on the particular port/board,
and specifying `scl` and `sda` may or may not be required or
allowed in this case.
- `scl` should be a pin object specifying the pin to use for SCL.
- `sda` should be a pin object specifying the pin to use for SDA.
- `freq` should be an integer which sets the maximum frequency
for SCL.
General Methods
---------------
.. only:: port_wipy
.. method:: I2C.init(mode, \*, baudrate=100000, pins=(SDA, SCL))
Initialise the I2C bus with the given parameters:
.. method:: I2C.init(scl, sda, \*, freq=400000)
- ``mode`` must be ``I2C.MASTER``
- ``baudrate`` is the SCL clock rate
- ``pins`` is an optional tuple with the pins to assign to the I2C bus.
Initialise the I2C bus with the given arguments:
.. only:: port_esp8266
.. method:: I2C.init(scl, sda, \*, freq=400000)
Initialise the I2C bus with the given arguments:
- `scl` is a pin object for the SCL line
- `sda` is a pin object for the SDA line
- `freq` is the SCL clock rate
- `scl` is a pin object for the SCL line
- `sda` is a pin object for the SDA line
- `freq` is the SCL clock rate
.. method:: I2C.deinit()
......@@ -102,8 +71,6 @@ General Methods
those that respond. A device responds if it pulls the SDA line low after
its address (including a write bit) is sent on the bus.
Note: on WiPy the I2C object must be in master mode for this method to be valid.
Primitive I2C operations
------------------------
......@@ -204,12 +171,3 @@ methods are convenience functions to communicate with such devices.
On WiPy the return value is the number of bytes written. Otherwise the
return value is `None`.
Constants
---------
.. data:: I2C.MASTER
for initialising the bus to master mode
Availability: WiPy.
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