1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
.. _machine.I2C:
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.
.. only:: port_wipy
Example::
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
Printing the i2c object gives you information about its configuration.
.. only:: port_wipy
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
Constructors
------------
.. only:: port_wipy
.. class:: machine.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).
Methods
-------
.. method:: i2c.deinit()
Turn off the I2C bus.
.. only:: port_wipy
.. method:: i2c.init(mode, \*, baudrate=100000, pins=(SDA, SCL))
Initialise the I2C bus with the given parameters:
- ``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.
.. method:: i2c.readfrom(addr, nbytes)
Read ``nbytes`` from the slave specified by ``addr``.
Returns a ``bytes`` object with the data read.
.. method:: i2c.readfrom_into(addr, buf)
Read into ``buf`` from the slave specified by ``addr``.
Returns the number of bytes read.
.. method:: i2c.writeto(addr, buf, \*, stop=True)
Write ``buf`` to the slave specified by ``addr``. Set ``stop`` to ``False``
if the transfer should be continued.
Returns the number of bytes written.
.. method:: i2c.readfrom_mem(addr, memaddr, nbytes, \*, addrsize=8)
Read ``nbytes`` from the slave specified by ``addr`` starting from the memory
address specified by ``memaddr``.
Param ``addrsize`` specifies the address size in bits.
Returns a ``bytes`` object with the data read.
.. method:: i2c.readfrom_mem_into(addr, memaddr, buf, \*, addrsize=8)
Read into ``buf`` from the slave specified by ``addr`` starting from the memory
address specified by ``memaddr``.
Param ``addrsize`` specifies the address size in bits.
Returns the number of bytes read.
.. method:: i2c.writeto_mem(addr, memaddr, buf, \*, addrsize=8)
Write ``buf`` to the slave specified by ``addr`` starting from the
memory address specified by ``memaddr``. Param ``addrsize`` specifies the
address size in bits.
Set ``stop`` to ``False`` if the transfer should be continued.
Returns the number of bytes written.
.. method:: i2c.scan()
Scan all I2C addresses from 0x01 to 0x7f and return a list of those that respond.
Only valid when in master mode.
Constants
---------
.. data:: I2C.MASTER
for initialising the bus to master mode
|
