Description
The PCF8574 I2C Expander is a versatile module that communicates via the I2C protocol, providing 8 additional digital input/output pins using only two microcontroller pins (SDA and SCL). It is perfect for projects that need extra GPIO pins without complex wiring. The module supports up to 8 devices on the same I2C bus with configurable addresses. Ideal for driving LEDs, reading buttons, controlling relays, and other digital I/O operations.
Key Features
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Adds 8 digital I/O pins via I2C interface
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Only uses 2 microcontroller pins (SDA, SCL)
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Address selectable via 3 address pins (A0, A1, A2)
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Compatible with Arduino, ESP32, ESP8266, and Raspberry Pi
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Low power consumption, suitable for battery-operated projects
Variants
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PCF8574 Standard I2C Expander Module
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PCF8574A Variant (alternate address range)
Specifications
| Feature | Details |
|---|---|
| I/O Pins | 8 (P0–P7) |
| Interface | I2C (SDA, SCL) |
| Address Pins | 3 (A0, A1, A2) |
| Operating Voltage | 3.3V – 5V |
| Max Current per Pin | 25 mA |
| Communication Speed | Up to 400 kHz |
Applications
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Expand GPIO for Arduino, ESP32, Raspberry Pi
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Drive multiple LEDs or relays
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Read multiple buttons or switches
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Control digital devices in IoT projects
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Microcontroller-based automation systems
Compatible Boards / Circuits
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Arduino Uno, Mega, Nano
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ESP32 / ESP8266
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Raspberry Pi (via I2C)
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Any microcontroller with I2C support
Reviews
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