PCF8570P datasheet by Philips Semiconductors

PCF8570P Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8570P can handle?
  The PCF8570P can handle I2C bus frequencies up to 400 kHz, but it's recommended to use a maximum frequency of 100 kHz for reliable operation.
• Can I use the PCF8570P as a level shifter between 3.3V and 5V systems?
  Yes, the PCF8570P can be used as a level shifter between 3.3V and 5V systems, but you need to ensure that the VCC pin is connected to the higher voltage (5V) and the I2C bus is properly terminated.
• How do I handle the internal pull-up resistors on the I2C bus?
  The PCF8570P has internal pull-up resistors on the I2C bus, but they are relatively weak (around 10 kΩ). You may need to add external pull-up resistors to ensure reliable operation, especially in noisy environments.
• Can I use the PCF8570P to drive LEDs or other high-current devices?
  No, the PCF8570P is not designed to drive high-current devices like LEDs. The output pins are limited to a maximum current of 20 mA, and you should use external transistors or drivers to handle higher currents.
• How do I reset the PCF8570P to its default state?
  You can reset the PCF8570P by cycling the power supply (VCC) or by sending a specific I2C command sequence (0x03, 0x00, 0x00, 0x00). However, be careful when using the latter method, as it may affect other devices on the I2C bus.