garrettsocling / adafruit_circuitpython_mcp3xxx

CircuitPython library for MCP300x SPI ADC's, may later support MCP320x as well

Introduction

CircuitPython library for the MCP3xxx series of analog-to-digital converters.

Currently supports:

• MCP3008: 8-Channel 10-Bit ADC With SPI Interface

Dependencies

This driver depends on:

• Adafruit CircuitPython
• Bus Device

Please ensure all dependencies are available on the CircuitPython filesystem. This is easily achieved by downloading the Adafruit library and driver bundle.

Usage Example

Single Ended

import busio
import digitalio
import board
from adafruit_mcp3xxx.mcp3008 import MCP3008
from adafruit_mcp3xxx.analog_in import AnalogIn

# create the spi bus
spi = busio.SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)

# create the cs (chip select)
cs = digitalio.DigitalInOut(board.D5)

# create the mcp object from MCP3008 class
mcp = MCP3008(spi, cs)

# create an analog input channel on pin 0
chan = AnalogIn(mcp, MCP3008.pin_0)

print('Raw ADC Value: ', chan.value)
print('ADC Voltage: ' + str(chan.voltage) + 'V')

Differential

import busio
import digitalio
import board
from adafruit_mcp3xxx.mcp3008 import MCP3008
from adafruit_mcp3xxx.differential_analog_in import DifferentialAnalogIn

# create the spi bus
spi = busio.SPI(clock=board.SCK, MISO=board.MISO, MOSI=board.MOSI)

# create the cs (chip select)
cs = digitalio.DigitalInOut(board.D5)

# create the mcp object from MCP3008 class
mcp = MCP3008(spi, cs)

# create a differential analog input channel with pin 0 and pin 1
chan = DifferentialAnalogIn(mcp, MCP3008.pin_0, MCP3008.pin_1)

print('Differential ADC Value: ', chan.value)
print('Differential ADC Voltage: ' + str(chan.voltage) + 'V')

Contributing

Contributions are welcome! Please read our Code of Conduct before contributing to help this project stay welcoming.

Building locally

Zip release files

To build this library locally you'll need to install the circuitpython-build-tools package.

python3 -m venv .env
source .env/bin/activate
pip install circuitpython-build-tools

Once installed, make sure you are in the virtual environment:

source .env/bin/activate

Then run the build:

circuitpython-build-bundles --filename_prefix adafruit-circuitpython-mcp3xxx --library_location .

Sphinx documentation

Sphinx is used to build the documentation based on rST files and comments in the code. First, install dependencies (feel free to reuse the virtual environment from above):

python3 -m venv .env
source .env/bin/activate
pip install Sphinx sphinx-rtd-theme

Now, once you have the virtual environment activated:

cd docs
sphinx-build -E -W -b html . _build/html

This will output the documentation to docs/_build/html. Open the index.html in your browser to view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to locally verify it will pass.