adafruit_mcp4728

Helper library for the Microchip MCP4728 I2C 12-bit Quad DAC

  • Author(s): Bryan Siepert

Implementation Notes

Hardware:

Software and Dependencies:

class adafruit_mcp4728.MCP4728(i2c_bus: I2C, address: int = 96)

Helper library for the Microchip MCP4728 I2C 12-bit Quad DAC.

Parameters:

  • i2c_bus (I2C) – The I2C bus the MCP4728 is connected to.

  • address (int) – The I2C device address. Defaults to 0x60

Quickstart: Importing and using the MCP4728

Here is an example of using the MCP4728 class. First you will need to import the libraries to use the sensor

import board
import adafruit_mcp4728

Once this is done you can define your board.I2C object and define your sensor object

i2c = board.I2C()   # uses board.SCL and board.SDA
mcp4728 = adafruit_mcp4728.MCP4728(i2c)

Now you have can give values to the different channels

mcp4728.channel_a.value = 65535  # Voltage = VDD
mcp4728.channel_b.value = int(65535 / 2)  # VDD/2
mcp4728.channel_c.value = int(65535 / 4)  # VDD/4
mcp4728.channel_d.value = 0  # 0V
save_settings() → None

Saves the currently selected values, Vref, and gain selections for each channel to the EEPROM, setting them as defaults on power up

sync_vrefs() → None

Syncs the driver’s vref state with the DAC

sync_gains() → None

Syncs the driver’s gain state with the DAC

reset() → None

Internal Reset similar to a Power-on Reset (POR). The contents of the EEPROM are loaded into each DAC input and output registers immediately

wakeup() → None

Reset the Power-Down bits (PD1, PD0 = 0,0) and Resumes Normal Operation mode

soft_update() → None

Updates all DAC analog outputs (VOUT) at the same time.

class adafruit_mcp4728.Channel(dac_instance: Literal[0, 1, 2, 3], cache_page: Dict[str, int], index: int)

An instance of a single channel for a multi-channel DAC.

Parameters:

  • dac_instance – Instance of the channel object

  • cache_page – cache page of the channel

  • index – Index of the channel

Note

All available channels are created automatically and should not be created by the user

property normalized_value: float

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

property value: int

The 16-bit scaled current value for the channel. Note that the MCP4728 is a 12-bit piece so quantization errors will occur

property raw_value: int

The native 12-bit value used by the DAC

property gain: Literal[1, 2]

Sets the gain of the channel if the Vref for the channel is Vref.INTERNAL. The gain setting has no effect if the Vref for the channel is `Vref.VDD`.

With gain set to 1, the output voltage goes from 0v to 2.048V. If a channel’s gain is set to 2, the voltage goes from 0V to 4.096V. gain Must be 1 or 2

property vref: Literal[0, 1]

Sets the DAC’s voltage reference source. Must be a VREF