PCA9555D datasheet by Philips Semiconductors

PCA9555D Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that PCA9555D can support?
  The PCA9555D can support I2C bus frequencies up to 400 kHz, but it is recommended to operate at 100 kHz or lower for reliable operation.
• How do I reset the PCA9555D?
  The PCA9555D can be reset by pulling the RESET pin low for at least 1 ms. This will reset the device to its default state.
• What is the purpose of the A0, A1, and A2 address pins?
  The A0, A1, and A2 address pins are used to set the I2C slave address of the PCA9555D. By connecting these pins to VCC or GND, the device can be assigned one of eight possible I2C addresses.
• Can I use the PCA9555D as a level translator?
  Yes, the PCA9555D can be used as a level translator between 1.8 V and 5 V logic levels. However, it is not recommended to use it as a level translator for high-speed signals.
• How do I configure the PCA9555D for input or output mode?
  The PCA9555D can be configured for input or output mode by writing to the Configuration Register (Register 06h). Setting a bit to 0 configures the corresponding pin as an input, while setting it to 1 configures it as an output.