CY8C9540A-24PVXIT is a multi-port I/O expander with onboard user EEPROM and several PWM outputs. It operates identically but differs in I/O pins, number of PWMs, and internal EEPROM size. It operates as two I2C devices. The first device is a multi-port I/O expander (single I2C address to access all ports through registers). The second device is a serial EEPROM. Dedicated configuration registers can be used to disable the EEPROM. The EEPROM uses 2-byte addressing to support the 28Kbyte EEPROM address space. The I/O expander's data pins can be independently assigned as inputs, outputs, quasi-bidirectional input/outputs, or PWM outputs. The individual data pins can be configured as open drain or collector, strong drive (10mA source, 25mA sink), resistively pulled up or down, or high impedance. The factory default configuration is pulled up internally.