Texas Instruments’ (TI) PCF8574 and PCF8574A are two-wire
I2C-bus to 8-bit parallel bus I/O expanders from TI’s I2C logic portfolio.
They are designed to provide a simple and cost-effective method to monitor and control several peripheral signals.
The difference between the PCF8574and PCF8574A is the I2C address:
PCF8574 has addresses ranging from 0x20 to 0x27 (up to eight PCF8574 devices may be used on the same I2C bus).
The PCF8574 and PCF8574A have addresses ranging from 0x38 to 0x3F (up to eight PCF8574A devices may be used on the same I2C bus).
• A total of 16 PCF8574 and PCF8574A devices may be used on the same I2C bus.
The PCF8574 and PCF8574A use the serial clock (SCL) and serial data (SDA) I2C lines to communicate with the bus controller.
Download Datenblatt PCF8574