Introduction

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CircuitPython module for the MCP4725 digital to analog converter.

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.

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 adafruit-circuitpython-mcp4725

To install system-wide (this may be required in some cases):

sudo pip3 install adafruit-circuitpython-mcp4725

To 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 adafruit-circuitpython-mcp4725

Usage Example

See examples/max4725_simpletest.py for a demo of the usage.

Contributing

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.

Table of Contents

Simple test

Ensure your device works with this simple test.

examples/mcp4725_simpletest.py
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# SPDX-FileCopyrightText: 2018 Tony DiCola for Adafruit Industries
# SPDX-License-Identifier: MIT

# Simple demo of setting the DAC value up and down through its entire range
# of values.
import board
import busio

import adafruit_mcp4725


# Initialize I2C bus.
i2c = busio.I2C(board.SCL, board.SDA)

# Initialize MCP4725.
dac = adafruit_mcp4725.MCP4725(i2c)
# Optionally you can specify a different addres if you override the A0 pin.
# amp = adafruit_max9744.MAX9744(i2c, address=0x63)

# There are a three ways to set the DAC output, you can use any of these:
dac.value = 65535  # Use the value property with a 16-bit number just like
# the AnalogOut class.  Note the MCP4725 is only a 12-bit
# DAC so quantization errors will occur.  The range of
# values is 0 (minimum/ground) to 65535 (maximum/Vout).

dac.raw_value = 4095  # Use the raw_value property to directly read and write
# the 12-bit DAC value.  The range of values is
# 0 (minimum/ground) to 4095 (maximum/Vout).

dac.normalized_value = 1.0  # Use the normalized_value property to set the
# output with a floating point value in the range
# 0 to 1.0 where 0 is minimum/ground and 1.0 is
# maximum/Vout.

# Main loop will go up and down through the range of DAC values forever.
while True:
    # Go up the 12-bit raw range.
    print("Going up 0-3.3V...")
    for i in range(4095):
        dac.raw_value = i
    # Go back down the 12-bit raw range.
    print("Going down 3.3-0V...")
    for i in range(4095, -1, -1):
        dac.raw_value = i

adafruit_mcp4725 - MCP4725 digital to analog converter

CircuitPython module for the MCP4725 digital to analog converter. See examples/mcp4725_simpletest.py for a demo of the usage.

  • Author(s): Tony DiCola, Carter Nelson

Implementation Notes

Hardware:

Software and Dependencies:

class adafruit_mcp4725.MCP4725(i2c, *, address=98)[source]

MCP4725 12-bit digital to analog converter. This class has a similar interface as the CircuitPython AnalogOut class and can be used in place of that module.

Parameters:
  • i2c (I2C) – The I2C bus.
  • address (int) – The address of the device if set differently from the default.
normalized_value

The DAC value as a floating point number in the range 0.0 to 1.0.

raw_value

The DAC value as a 12-bit unsigned value. This is the the true resolution of the DAC and will never peform scaling or run into quantization error.

save_to_eeprom()[source]

Store the current DAC value in EEPROM.

value

The DAC value as a 16-bit unsigned value compatible with the AnalogOut class.

Note that the MCP4725 is still just a 12-bit device so quantization will occur. If you’d like to instead deal with the raw 12-bit value use the raw_value property, or the normalized_value property to deal with a 0…1 float value.

Indices and tables