LCD + #pcf8574 8-bit I/O expander for I2C bus #ardunio #stm #wch

The combination of an LCD screen and the PCF8574 I/O expander for I2C communication is a popular setup in electronics projects, especially with platforms like Arduino, STM32, and WCH (e.g., CH32 microcontrollers). This setup allows for easy control of an LCD display with minimal wiring, making it ideal for projects where space or pin availability is limited. Here’s an in-depth look at how these components work together and the technical details involved.

1. Introduction to the PCF8574 I/O Expander

The PCF8574 is an 8-bit I/O expander IC that uses the I2C bus (Inter-Integrated Circuit) for communication. It effectively increases the number of I/O pins available to a microcontroller like an Arduino, STM32, or WCH MCU by using only two wires, SCL (clock) and SDA (data). This makes it a great solution for interfacing with devices like LCDs that require multiple pins, without consuming too many GPIO pins from the microcontroller.

Key features of the PCF8574:

• 8-bit bidirectional I/O pins.
• I2C interface, allowing communication over two wires.
• Each PCF8574 can be given a unique I2C address, enabling multiple devices on the same bus.