Introduction
CircuitPython library for Texas Instruments TCA9555 Low-Voltage 16-Bit I2C and SMBus I/O Expander with Input / Output and Polarity Inversion.
Dependencies
This driver depends on:
Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle or individual libraries can be installed using circup.
Installing from PyPI
On supported GNU/Linux systems like the Raspberry Pi, you can install the driver locally from PyPI. To install for current user:
pip3 install community-circuitpython-tca9555To install system-wide (this may be required in some cases):
sudo pip3 install community-circuitpython-tca9555To install in a virtual environment in your current project:
mkdir project-name && cd project-name
python3 -m venv .env
source .env/bin/activate
pip3 install community-circuitpython-tca9555Usage Example
Create an instance of TCA9555 expander. This defaults to all 16 pins set as inputs with no polarity conversion.
from community_tca9555 import TCA9555
# If the board has I2C defined
expander = TCA9555(board.I2C()) # Use default address of 0x20
# Else specify the specific pins
expander = TCA9555(busio.I2C(scl=board.GP5, sda=board.GP4)) # for the RP PicoSet the low 8 bits as inputs and the high 8 bits as outputs.
# set all 16 pins at once
expander.configuration_ports = 0x00FF
# or
# set port 0 (8bits) and port 1 (8 bits)
expander.configuration_port_0 = 0xFF # Inputs
expander.configuration_port_1 = 0x00 # Outputs
# or
# set each pin individually
expander.configuration_port_0_pin_0 = True # Input
# ...
expander.configuration_port_1_pin_7 = False # OutputSet pins 6 and 7 of both port 0 and port 1 as polarity inverted.
# Set polarity inversion state for individual pins.
expander.polarity_inversion_port_0_pin_6 = True # Inverted
expander.polarity_inversion_port_0_pin_7 = True
expander.polarity_inversion_port_1_pin_6 = True
expander.polarity_inversion_port_1_pin_7 = True
# or
# Set an 8bit port at once
expander.polarity_inversion_port_0 = 0xC0 # Just bits 6 and 7
# or
# Set all 16bits at once
expander.polarity_inversions = 0xC0C0Read the input pins.
input_state = expander.input_port_0
print("Inputs: {:08b}".format(input_state))Set the state of the output pins.
expander.output_port_1 = 0x42Contributing
Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.
Documentation
For information on building library documentation, please check out this guide.
