PCF8574T datasheet by NXP Semiconductors

PCF8574T Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8574T can support?
  The PCF8574T can support I2C bus frequencies up to 400 kHz, but it's recommended to operate at 100 kHz for reliable operation.
• How do I reset the PCF8574T?
  The PCF8574T can be reset by pulling the SCL line low for at least 10 ms. This will reset the device and clear all registers.
• What is the maximum current that the PCF8574T can sink or source?
  The PCF8574T can sink or source up to 25 mA per I/O pin, but the total current should not exceed 100 mA.
• Can I use the PCF8574T as an input expander?
  Yes, the PCF8574T can be used as an input expander. It can read the state of the input pins and transmit the data to the I2C bus.
• How do I address multiple PCF8574T devices on the same I2C bus?
  You can address multiple PCF8574T devices on the same I2C bus by connecting the A0, A1, and A2 pins to VCC or GND to set the device address.