PCA9556

  The PCA9556 is a silicon CMOS circuit which provides parallel input/output expansion for SMBus applications. The PCA9556 consists of an 8-bit input port register, 8-bit output port register, and an SMBus interface. PCA9556 has low current consumption and a high impedance open drain output pin, I/O0.
 
   The SMBus system master can reset the PCA9556 in the event of a timeout by asserting a LOW on the reset input. The SMBus system master can also invert the PCA9556 inputs by writing to their active HIGH polarity inversion bits. Finally, the SMBus system master can enable the PCA9556!fls I/Os as either inputs or outputs by writing t their I/O configuration bits.