.. seo:: description: Instructions for setting up MCP3204 & MCP3208 12-Bit Analog to Digital Converter in ESPHome. image: mcp3204.jpg

MCP3204 & MCP3208 12-Bit A/D Converters

The Microchip Technology Inc. MCP3204 & MCP3208 devices are successive approximation 12-bit Analog-to-Digital (A/D) converters with on-board sample and hold circuitry. This ESPHome component provides support for both device types. You may configure both devices as :code:mcp3204 and select the channel count per your variant.

.. figure:: mcp3204.jpg :align: center :width: 50.0% :alt: MCP3204 image

Component/Hub

The MCP3204 component allows you to use MCP3204 or MCP3208 12-Bit A/D Converter (datasheet <https://ww1.microchip.com/downloads/en/DeviceDoc/21298e.pdf>_) in ESPHome. The MCP3204 is a 4-channel and MCP3208 is an 8-channel device. It uses the :doc:SPI Bus <spi> for communication.

Once configured, you can use any of the 4 or 8 pins (depending on device variant) as sensors for your projects.

Each pin will respond with a voltage calculated off of the :code:reference_voltage (default is 3.3V). The voltage is calculated as :code:reference_voltage * value / 4096 (the percentage of VREF for a 12-bit ADC).

Usually, you will set :code:reference_voltage to the VREF pin voltage.

.. code-block:: yaml

mcp3204:
    cs_pin: GPIOXX
    reference_voltage: 3.3V

Configuration variables:

id (Required, :ref:config-id): The id to use for this MCP3204 component.
cs_pin (Required, :ref:config-pin_schema): The SPI cable select pin to use.
reference_voltage (Optional, float): The reference voltage. Defaults to :code:3.3V.

Sensor

The :code:mcp3204 sensor platform allows you to use MCP3204 or MCP3208 12-Bit A/D sensor channels with ESPHome. First, setup an :ref:MCP3204 Hub <mcp3204-component> for your MCP3204/8 sensor and then use this sensor platform to create individual sensors that will report the voltage to Home Assistant.

.. code-block:: yaml

sensor:
  - platform: mcp3204       # Single-ended mode: pin 0 of MCP3204
    id: solar_voltage
    number: 0

  # Pin 7 of MCP3208 in single-ended mode (for MCP3208, use pin numbers 0-7)
  - platform: mcp3204
    id: supply_voltage
    number: 7

  # Differential mode: Measures voltage between channel 0 (IN+) and channel 1 (IN–)
  - platform: mcp3204
    id: differential_sensor
    number: 0               # Channel 0 (IN+), paired with 1 (IN–) in differential mode
    diff_mode: true         # Enable differential mode
    name: "Differential Voltage CH0–CH1"

Configuration variables:

mcp3204_id (Required, :ref:config-id): ID of the parent MCP3204 component.
number (Required, int): The channel number (0-3 for MCP3204, 0-7 for MCP3208).
diff_mode (Optional, bool): Enables differential mode. If :code:true, the ADC measures the voltage difference between the selected channel and its paired channel (see chip datasheet). Defaults to :code:false (single-ended mode).
update_interval (Optional, :ref:config-time): Interval to update the sensor. Defaults to :code:60s.
All other options from :ref:Sensor <config-sensor>.

.. note:: In differential mode, channel pairing depends on MCP3204/3208 datasheet. The voltage reading represents the difference between the positive input (IN+) and negative input (IN-). In single-ended mode, ADC measures each channel against ground.

MCP3204 & MCP3208 12-Bit A/D Converters

Component/Hub

Sensor

See Also