The IIC TWI Serial Interface Board Port 1602 2004 LCD LCD1602 Adapter Plate LCD Adapter Converter Module PCF8574 is a compact I2C to HD44780 LCD adapter that enables a standard LCD1602 (16x2) or LCD2004 (20x4) character display to be driven over a two‑wire I2C (TWI) bus. It uses the PCF8574 I/O expander to convert serial I2C signals into the parallel control and data signals required by the LCD, simplifying wiring and reducing microcontroller pin usage without altering the LCD module. Key benefits Reduces I/O pin usage: drive a classic HD44780 LCD through a single I2C bus instead of multiple GPIO pins. Simplifies wiring for compact projects: a single I2C connection carries power, ground, and display control. Broad compatibility: designed for standard LCD1602 and LCD2004 modules that use the HD44780 controller, via the PCF8574 expander. Flexible integration: suitable for development platforms and microcontrollers with I2C support, such as Arduino and Raspberry Pi, enabling quick prototyping and stable operation. Simple upgrade path: preserves the use of widely available LCD modules while adding modern I2C interfacing. Key attributes Functionality: I2C (TWI) serial interface to control LCD1602 (16x2) and LCD2004 (20x4) displays through a PCF8574 I/O expander. Compatibility: works with standard LCD modules that use the HD44780 controller; adapter plate supports 1602 and 2004 types via PCF8574 backplane. Size and form factor: compact adapter plate designed to fit standard LCD modules; intended to minimize extra wiring and device footprint. Material and construction: PCB based adapter plate that provides the I2C to LCD signal conversion. Performance considerations: enables reliable serial control over I2C; reduces pin count on the host controller and simplifies integration on projects with limited GPIO resources. Specifications overview (where applicable) Interface: I2C (TWI) serial communication to drive HD44780 LCDs through PCF8574 LCD types supported: LCD1602 (16x2) and LCD2004 (20x4) Driver component: PCF8574 I/O expander Module type: LCD adapter/converter plate for standard LCD modules Intended use: enables I2C control of traditional character LCD displays via a compact interface Compatibility and use considerations Suitable for standard LCD modules that use the HD44780 controller family (1602 and 2004 sizes) Requires a host controller with I2C support and appropriate software libraries to drive the LCD via the PCF8574 backplane Voltage and voltage levels depend on the specific board and LCD module; verify compatibility with your power supply and I2C bus voltage before use Typical use cases Arduino projects that display sensor data or status messages on a 1602 LCD while keeping GPIO usage low Raspberry Pi projects needing a compact LCD output for system information without consuming multiple GPIO pins Embedded prototypes or educational kits where a simple I2C interface to a 16x2 or 20x4 LCD enhances portability and ease of wiring How to use Connect the LCD1602 or LCD2004 module to the adapter plate according to the LCD's standard parallel interface Connect the adapter plate to the host device via the I2C bus (SDA and SCL lines) and provide power and ground as required Use a common I2C LCD library or code sample to initialize the display and write text, leveraging the PCF8574 backplane through the I2C interface Notes This adapter is designed to work with standard LCD modules and PCF8574 based I2C backplanes; confirm LCD type (1602 or 2004) and voltage compatibility with your system Check your LCD module for the backlight and contrast adjustments on the LCD itself, as these aspects are typically separate from the I2C adapter When integrating with microcontrollers or SBCs, select appropriate I2C addresses and libraries compatible with your development environment This description remains aligned with the products intended brand, model, and features: an IIC TWI serial interface board that serves as an LCD1602/LCD2004 adapter using PCF8574 to enable I2C control of standard HD44780 LCD modules.