pyi2c 0.2.1

A useful i2c package for Pi

A useful i2c Python3 package for Pi

It is a simple I2C interface based on smbus2.

1. Installation

Via pip

pip3 install pyi2c

2. API and example

2.1 I2C(bus_n)

2.1.1 declare

from pyi2c import I2C

# Create i2c
BUS_N = 0 # 0 or 1 or 2. Change this to yours
i2c = I2C(BUS_N)

ADDR = 0x38 # Change this to yours

2.1.2 scan()

Scan all I2C devices on the same BUS.

i2c.scan()

    00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
00: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- 38 -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- 5a -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
80: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --

2.1.3 write(ADDR, data)

Return nothing

• data can be a byte or list of bytes.

WRITE0 = 0x00 # Change this to yours
i2c.write(ADDR, WRITE0)

# or write multi bytes, up to 64 bytes
WRITE1 = 0x01 # Change this to yours
i2c.write(ADDR, [WRITE0, WRITE1])

2.1.3 read(ADDR, byte_size=1)

Return byte, or list of bytes if byte_size >= 0

• byte_size can be empty (default is 1)

read_data = i2c.read(ADDR)

# or set length of reading bytes
byte_size = 2
read_data = i2c.read(ADDR, byte_size)
print( len(read_data) )
# 2

2.1.4 writeread(ADDR, data, byte_size=1)

Return byte, or list of bytes if byte_size >= 0

• data can be a byte or list of bytes.
• byte_size can be empty (default is 1)

# First write and read rapidly one byte
read_data = i2c.writeread(ADDR, WRITE0)

# These also work
read_data = i2c.writeread(ADDR, [WRITE0, WRITE1])
read_data = i2c.writeread(ADDR, [WRITE0, WRITE1], byte_size)

2.2 I2CDevice(bus_n, addr)

It is extension of I2C, but contains a I2C device's address. So it is not need to write address any more after declare.

2.2.1 Declare

from pyi2c import I2CDevice

BUS_N = 0
ADDR = 0x38

aht10 = I2CDeivce(BUS_N, ADDR)

2.2.2 write(data)

As the same as write(addr, data) in I2C, but does not need address.

2.2.3 read(byte_size=1)

As the same as read(addr, byte_size) in I2C, but does not need address.

2.2.4 writeread(data, byte_size=1)

As the same as writeread(addr, data, byte_size=1) in I2C, but does not need address.

2.3 getBit(byte, bin_n, bin_m=-1)

• bin_n should be >= 0
• bin_m can be empty (default is -1 but will overwrote with bin_n)
• bin_n or bin_m can be larger than byte's size

from pyi2c import getBit

byte = 0x5a # Any byte data
print( bin(byte) )
# '0b1011010'

• Get bit #n of byte

print( getBit(byte, 0) )
# 0

print( getBit(byte, 1) )
# 1

• Get multi bits from #n to #m of byte

print( getBit(byte, 4, 3) )
# 3 = 0b10
print( getBit(byte, 3, 4) )
# 3 = 0b10, the same as previous

• Recommend usage

if getBit(byte, 4) == 0b1:
    print('hoge')
# 'hoge'

For developers

Build

python3 -m build

Upload

python3 -m twine upload dist/*

Reference

• Packaging Python Projects
• smbus2 GitHub
• Pure Python I2C : access to I2C components through serial or parallel interface.