PCA9550D,118 datasheet by NXP Semiconductors

PCA9550D,118 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCA9550D can support?
  The PCA9550D can support I2C bus frequencies up to 400 kHz.
• How do I configure the PCA9550D to use an external reset signal?
  To use an external reset signal, connect the reset signal to the RST pin and set the RST_POL bit in the Configuration Register (address 0x02) to 1. This will allow the external reset signal to override the internal reset.
• What is the purpose of the internal pull-up resistors on the I2C bus lines?
  The internal pull-up resistors on the I2C bus lines are used to ensure that the bus lines are pulled up to a logic high level when no device is actively driving the bus. This helps to prevent bus contention and ensures reliable communication.
• How do I use the PCA9550D to control LEDs?
  To use the PCA9550D to control LEDs, connect the LEDs to the output pins of the device and use the Output Port Register (address 0x03) to set the output state of the pins. You can also use the Auto-Increment Register (address 0x04) to automatically increment the output state of the pins.
• What is the maximum current that the PCA9550D can sink or source on each output pin?
  The PCA9550D can sink or source up to 25 mA of current on each output pin.