PCA9558

The PCA9558 is a highly integrated, multi-function device that is composed of a 5-bit multiplexed/1-bit latched 6-bit I2C/SMBus EEPROM, an 8-bit I/O expander and a 2K serial EEPROM with write protect. The PCA9558 integrates these commonly used components into a single chip to reduce component count and board space requirements and is useful in computer, server and telecom/networking applications.

Multiplexed/latched EEPROM - used to select digital information between a set of 5-bits of default hardware inputs and an alternative set of inputs provided by the I²C/SMBus interface and stored in the EEPROM. Examples of this type of selection include processor voltage configuration of PCA9558 or processor vendor identification (VID). The multiplexed/latched EEPROM PCA9558 can also be used to replace DIP switches or jumpers, since the settings can be easily changed via I²C/SMBus without having to power down the equipment to open the cabinet. The non-volatile memory retains the most current setting selected before the power is turned off.

8-bit I/O expander - used to control, monitor or collect remote information or power LEDs. Monitored or collected information of PCA9558 can be read through the I²C/SMBus or can be stored in the internal EEPROM.

2K serial EEPROM - used to store information such as card identification or revision/maintenance history on every motherboard/linecard and can be read or written via I²C/SMBus when required. The PCA9558 has 1 address pin allowing up to 2 devices to be placed on the same I²C bus or SMBus.