Smbus Library

  1. Python Smbus Library
  2. Micropython Smbus Library

March 2019 AN4502 Rev 3 1/74 AN4502 Application note STM32 SMBus/PMBusTM Expansion Package for STM32CubeTM Introduction This document describes the X-CUBE-SMBUS, STM32 SMBus/PMBus™ (system. Smbus2 - A drop-in replacement for smbus-cffi/smbus-python. Class smbus2.SMBus (bus=None, force=False) ¶. Blockprocesscall (i2caddr, register, data, force=None) ¶. Executes a SMBus Block Process Call, sending a variable-size data block and receiving another variable-size response. Drivers Library. To find the latest driver for your computer we recommend running our Free Driver Scan. SM Bus Controller - Driver Download. Vendor:. Product: SM Bus Controller. Hardware Class: Net.

smbus2 - A drop-in replacement for smbus-cffi/smbus-python

class smbus2.SMBus(bus=None, force=False)
block_process_call(i2c_addr, register, data, force=None)

Executes a SMBus Block Process Call, sending a variable-size datablock and receiving another variable-size response

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to read/write to
  • data (list) – List of bytes
  • force (Boolean) –
Returns:

List of bytes

Return type:

list

close()

Close the i2c connection.

enable_pec(enable=True)

Enable/Disable PEC (Packet Error Checking) - SMBus 1.1 and later

Parameters:enable (Boolean) –
i2c_rdwr(*i2c_msgs)

Combine a series of i2c read and write operations in a singletransaction (with repeated start bits but no stop bits in between).

This method takes i2c_msg instances as input, which must be createdfirst with i2c_msg.read() or i2c_msg.write().

Python Smbus Library

Parameters:i2c_msgs (i2c_msg) – One or more i2c_msg class instances.
Return type:None
open(bus)

Open a given i2c bus.

Smbus Library
Parameters:bus (int or str) – i2c bus number (e.g. 0 or 1)or an absolute file path (e.g. ‘/dev/i2c-42’).
Raises:TypeError – if type(bus) is not in (int, str)
pec

Get and set SMBus PEC. 0 = disabled (default), 1 = enabled.

process_call(i2c_addr, register, value, force=None)

Executes a SMBus Process Call, sending a 16-bit value and receiving a 16-bit response

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to read/write to
  • value (int) – Word value to transmit
  • force (Boolean) –
Return type:
read_block_data(i2c_addr, register, force=None)

Read a block of up to 32-bytes from a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Start register
  • force (Boolean) –
Returns:

List of bytes

Return type:

list

Micropython Smbus Library

read_byte(i2c_addr, force=None)

Read a single byte from a device.

Return type:
Parameters:
  • i2c_addr (int) – i2c address
  • force (Boolean) –
Returns:

Read byte value

read_byte_data(i2c_addr, register, force=None)

Read a single byte from a designated register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to read
  • force (Boolean) –
Returns:

Read byte value

Return type:
read_i2c_block_data(i2c_addr, register, length, force=None)

Read a block of byte data from a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Start register
  • length (int) – Desired block length
  • force (Boolean) –
Returns:

List of bytes

Return type:

list

read_word_data(i2c_addr, register, force=None)

Read a single word (2 bytes) from a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to read
  • force (Boolean) –
Returns:

2-byte word

Return type:
write_block_data(i2c_addr, register, data, force=None)

Write a block of byte data to a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Start register
  • data (list) – List of bytes
  • force (Boolean) –
Return type:
write_byte(i2c_addr, value, force=None)

Write a single byte to a device.

Parameters:
  • i2c_addr (int) – i2c address
  • value (int) – value to write
  • force (Boolean) –
write_byte_data(i2c_addr, register, value, force=None)

Write a byte to a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to write to
  • value (int) – Byte value to transmit
  • force (Boolean) –
Return type:
write_i2c_block_data(i2c_addr, register, data, force=None)

Write a block of byte data to a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Start register
  • data (list) – List of bytes
  • force (Boolean) –
Return type:
write_quick(i2c_addr, force=None)

Perform quick transaction. Throws IOError if unsuccessful.:param i2c_addr: i2c address:type i2c_addr: int:param force::type force: Boolean

write_word_data(i2c_addr, register, value, force=None)

Write a single word (2 bytes) to a given register.

Parameters:
  • i2c_addr (int) – i2c address
  • register (int) – Register to write to
  • value (int) – Word value to transmit
  • force (Boolean) –
Return type:
class smbus2.i2c_msg

As defined in i2c.h.

addr

Structure/Union member

buf

Structure/Union member

flags

Structure/Union member

len

Structure/Union member

static read(address, length)

Prepares an i2c read transaction.

Parameters:
  • address – Slave address.
  • length – Number of bytes to read.
Type:

address: int

Type:

length: int

Returns:

New i2c_msg instance for read operation.

Return type:
static write(address, buf)

Prepares an i2c write transaction.

Parameters:
  • address (int) – Slave address.
  • buf (list) – Bytes to write. Either list of values or str.
Returns:

New i2c_msg instance for write operation.

Return type:
Latest version

Released:

smbus2 is a drop-in replacement for smbus-cffi/smbus-python in pure Python

Project description

A drop-in replacement for smbus-cffi/smbus-python in pure Python

Smbus

smbus2 is (yet another) pure Python implementation of of the python-smbus package.

It was designed from the ground up with two goals in mind:

  1. It should be a drop-in replacement of smbus. The syntax shall be the same.
  2. Use the inherent i2c structs and unions to a greater extent than other pure Python implementations like pysmbus does. By doing so, it will be more feature complete and easier to extend.

Currently supported features are:

  • Get i2c capabilities (I2C_FUNCS)
  • SMBus Packet Error Checking (PEC) support
  • read_byte
  • write_byte
  • read_byte_data
  • write_byte_data
  • read_word_data
  • write_word_data
  • read_i2c_block_data
  • write_i2c_block_data
  • write_quick
  • process_call
  • read_block_data
  • write_block_data
  • block_process_call
  • i2c_rdwr - combined write/read transactions with repeated start

It is developed on Python 2.7 but works without any modifications in Python 3.X too.

More information about updates and general changes are recorded in the change log.

smbus2 installs next to smbus as the package, so it's not really a 100% replacement. You must change the module name.

Example 1a: Read a byte

Example 1b: Read a byte using 'with'

This is the very same example but safer to use since the smbus will be closed automatically when exiting the with block.

Example 1c: Read a byte with PEC enabled

Same example with Packet Error Checking enabled.

Example 2: Read a block of data

You can read up to 32 bytes at once.

Smbus Library

Example 3: Write a byte

Example 4: Write a block of data

It is possible to write 32 bytes at the time, but I have found that error-prone. Write less and add a delay in between if you run into trouble.

Starting with v0.2, the smbus2 library also has support for combined read and write transactions. i2c_rdwr is not really a SMBus feature but comes in handy when the master needs to:

  1. read or write bulks of data larger than SMBus' 32 bytes limit.
  2. write some data and then read from the slave with a repeated start and no stop bit between.

Each operation is represented by a i2c_msg message object.

Example 5: Single i2c_rdwr

Example 6: Dual i2c_rdwr

To perform dual operations just add more i2c_msg instances to the bus call:

Example 7: Access i2c_msg data

All data is contained in the i2c_msg instances. Here are some data access alternatives.

From PyPi with pip:

From conda-forge using conda:

Installation from source code is straight forward:

Release historyRelease notifications | RSS feed

0.4.1

0.4.0

0.3.0

0.2.3

0.2.2

0.2.1

0.2.0

0.1.5

0.1.4

0.1.3

0.1.2

0.1.1

0.1.0

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for smbus2, version 0.4.1
Filename, sizeFile typePython versionUpload dateHashes
Filename, size smbus2-0.4.1-py2.py3-none-any.whl (11.5 kB) File type Wheel Python version py2.py3 Upload dateHashes
Filename, size smbus2-0.4.1.tar.gz (16.8 kB) File type Source Python version None Upload dateHashes
Close

Hashes for smbus2-0.4.1-py2.py3-none-any.whl

Hashes for smbus2-0.4.1-py2.py3-none-any.whl
AlgorithmHash digest
SHA2568b1e70cda011b6fb3caf8377a1084f73a5aa99392b78529f140b0a3f06468f6c
MD547c994cf8cb7207a922c748fdedfd91c
BLAKE2-256c8bf62ef029fb7077fc87c3539f7365859bccc6cedb2bb20796b737b788c8d09
Close

Hashes for smbus2-0.4.1.tar.gz

Hashes for smbus2-0.4.1.tar.gz
AlgorithmHash digest
SHA2566276eb599b76c4e74372f2582d2282f03b4398f0da16bc996608e4f21557ca9b
MD5ea4bba25b43863aecd6ec33b2252fdae
BLAKE2-256d933787448c69603eec96af07d36f7ae3a7e3fce4020632eddb55152dc903233