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Smbus Library

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Has ANYONE found any better documentation on smbus than that erazer wiki site? The page there is from 2006, and is very rudimentary. I'm trying to figure out, for instance, what the parameters for the commands are (esp. The 'cmd' parameter). The pydoc site is even more useless, as it has nothing on smbus. Driver download page for the ATI SMBus by Video. To use the I2C library, you need to: #include. In your program. Programs need to be linked with -lwiringPi as usual. You can still use the standard system commands to check the I2C devices, and I recommend you do so – e.g. The i2cdetect program.

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

Python i2c smbus library
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()
Python

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().

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

Open a given i2c bus.

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

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:

I2c Smbus Library

Library
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)
Smbus Library
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().

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

Open a given i2c bus.

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

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:

I2c Smbus Library

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

Raspberry Pi Python Smbus Library

len

Structure/Union member

static read(address, length)

Micropython Smbus Library

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:
MSP430 microcontrollers MSP430G2213—16 MHz MCU with 2KB Flash, 256B SRAM, comparator, UART/SPI/I2C, timerMSP430G2233—16 MHz MCU with 2KB Flash, 256B SRAM, comparator, UART/SPI/I2C, timerMSP430G2303—16 MHz MCU with 4KB Flash, 256B SRAM, UART/SPI/I2C, timerMSP430G2313—16 MHz MCU with 4KB Flash, 256B SRAM, comparator, UART/SPI/I2C, timerMSP430G2333—16 MHz MCU with 4KB Flash, 256B SRAM, 10-bit ADC, UART/SPI/I2C, timerMSP430G2353—16 MHz MCU with 4KB Flash, 256B SRAM, 10-bit ADC, comparator, UART/SPI/I2C, timerMSP430G2453—16 MHz MCU with 8KB Flash, 512B SRAM, 10-bit ADC, comparator, UART/SPI/I2C, timerMSP430G2453-Q1—Automotive 16-MHz MCU with 8-kb Flash, 512-B SRAM, 10-bit ADC, comparator, UART/SPI/I2C, timerMSP430G2513—16 MHz MCU with 16KB FLASH, 512B SRAM, comparator, UART/SPI/I2C, timerMSP430G2533—16 MHz MCU with 16KB Flash, 512B SRAM, 10-bit ADC, UART/SPI/I2C, timerMSP430G2553-Q1—Automotive 16-MHz MCU with 16-kb Flash, 512B SRAM, 10-bit ADC, comparator, UART/SPI/I2C, timerMSP430G2744—16 MHz MCU with 32KB Flash, 1KB SRAM, 10-bit ADC, UART/SPI/I2C, timer




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