Easy MicroPython interface for the MCP4725 DAC.

Developed for a hobby project, it turns this :

value = max(0, min(4095, int(2792)))
buf = bytearray(3)
buf[0] = 0x40 
buf[1] = value >> 4
buf[2] = (value & 0xF) << 4
self.i2c.writeto(self.address, buf)

into this:

dac.set_voltage(2.25)

Drop mcp4725.py on your board's flash memory or your project folder, then :

from machine import I2C, Pin
from mcp4725 import MCP4725 # Import the driver's class

# Create an I2C bus
i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)

# Create an instance of MCP4725 on that bus, here with a reference VCC of 3.3V
dac = MCP4725(i2c, vcc=3.3)

# And you can now control the DAC in various manners:
dac.set_value(2048)          # Set raw 12-bit value
dac.set_voltage(1.65)        # Or set the voltage directly
dac.set_value_norm(0.5)      # Or set a ratio from 0.0 - 1.0

See mcp4725_quickstart.py for a more in-depth example.

• set_voltage() cannot actually determine voltage and requires the correct vcc reference voltage to work as expected (the voltage supplied to your MCP4725, e.g., 3.3 or 5.0).
• All input values are clamped to valid ranges (overflows will not error).
• Compatibility functions provided for clone/nonstandard modules that fail with the standard one.

• No explicit error handling for I2C bus errors (exceptions will propagate).
• Does not detect device presence or bus lock-up.

This project is licensed under the MIT License – see the LICENSE file for details.

Jean-Marie Prévost https://github.com/JeanMariePrevost