Is PCF8574 8-bit I2C GPIO Expander Compatible with Home Assistant (ESPHome)?

Verdict Badge

VERDICT: [ COMPATIBLE (MANUAL CONFIG REQUIRED) ]

Protocol: I2C Bus / 3.3V

Bridge Needed: NO

Hardware Safety & Electrical Verification

Electrical parameters & logic voltage safety limits before powering ICs

🟢 3.3V Native Direct Hookup 🧪 Verified in Lab

Power Input 5V DC via USB-C / VBUS

GPIO Logic Voltage 3.3V Logic Level — Level Shifter Required for 5V peripherals

Current Profile Peak Tx Current: ~180mA to ~250mA @ 3.3V

Ingress Protection None (Exposed Board — Enclosure Required)

## Compatibility Overview

I2C GPIO expander module adding 8 additional digital input/output pins to ESP8266 or ESP32 microcontrollers.

Interactive Pinout & Wiring Diagram

Hover over any pin to view voltage limits and pull-up specifications

VCC

3.3V Power

GND

Ground Common

SDA / TX

Data Line (GPIO 21)

SCL / RX

Clock Line (GPIO 22)

CS / INT

Chip Select (GPIO 19)

## Technical Specification Matrix

Feature / Attribute	Specification / Status
Hardware Protocol	I2C Bus / 3.3V
Bridge Required	NO
Border Router Needed	None
Hardware Capabilities & Peripherals	8x Expanded GPIO Inputs Output Pins Note: Exposing entities to Home Assistant requires corresponding YAML component config.
Pairing Complexity	Plug-and-Play
Factory Reset Instruction	Hold FLASH button on power up.

## Step-by-Step Pairing Guide

Factory Reset Device

Hold FLASH button on power up.

Initialize Pairing Mode on Home Assistant (ESPHome)

Open Home Assistant (ESPHome) administration console, navigate to Integrations / Add Device, and start pairing scanner.

Confirm Entity Binding & State Verification

Verify that primary entities (8x Expanded GPIO Inputs, Output Pins) report live state changes inside Home Assistant (ESPHome).

Production Code Generator & Preset Toolkit

Pre-configured pinouts & drivers for PCF8574 8-bit I2C GPIO Expander

SDA Pin: SCL Pin:

Test in Wokwi Simulator ↗ | Real-time pin binding active

👥 Community Verified Database Continuous hardware testing updates

Report a Pinout Error or Submit Tested Code Snippets

Found a pin mapping quirk or built a custom ESPHome YAML driver for PCF8574 8-bit I2C GPIO Expander? Help us keep this matrix 100% accurate.

## Frequently Asked Questions

Does this device operate in Offline Mode?

100% local I2C bus I/O expander.

What is the expected Battery Life & Power specification?

3.3V VCC I2C SDA=GPIO4 (D2) SCL=GPIO5 (D1).

How does Signal Mesh & Range Extension function?

Wi-Fi 802.11b/g/n.