PCA9555PW datasheet by NXP Semiconductors

PCA9555PW Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCA9555PW can support?
  The PCA9555PW can support I2C bus frequencies up to 400 kHz.
• How do I configure the PCA9555PW to use the internal oscillator?
  To use the internal oscillator, set the OSCEN bit in the Configuration Register (address 0x01) to 1. This will enable the internal oscillator and allow the device to operate without an external clock source.
• What is the purpose of the reset pin (RST) on the PCA9555PW?
  The reset pin (RST) is an active-low input that resets the PCA9555PW to its power-on state. When the RST pin is pulled low, the device resets and all registers are set to their default values.
• How do I use the PCA9555PW to control LEDs?
  The PCA9555PW can be used to control LEDs by connecting the LEDs to the output ports (P0-P7) and using the Output Port Register (address 0x02) to set the output values. The device can also be configured to use the internal oscillator to generate a PWM signal for LED dimming.
• What is the maximum current that the PCA9555PW can sink or source on each output port?
  The PCA9555PW can sink or source up to 25 mA of current on each output port.