General description
The PCA9500 is an 8-bit I/O expander with an on-board 2-kbit EEPROM.
The I/O expander's eight quasi-bidirectional data pins can be independently assigned as inputs or outputs to monitor board level status or activate indicator devices such as LEDs. The system master writes to the I/O configuration bits in the same way as for the PCF8574. The data for each input or output is kept in the corresponding Input or Output register. The system master can read all registers.
The EEPROM can be used to store error codes or board manufacturing data for read-back by application software for diagnostic purposes and is included in the I/O expander package.

FEATUREs
8 general purpose input/output expander/collector
Drop-in replacement for PCF8574 with integrated 2-kbit EEPROM
Internal 256×8 EEPROM
Self timed write cycle
4 byte page write operation
I2C-bus and SMBus interface logic
Internal power-on reset
Noise filter on SCL/SDA inputs
3 address pins allowing up to 8 devices on the I2C-bus/SMBus
No glitch on power-up
Supports hot insertion
Power-up with all channels configured as inputs
Low standby current
Operating power supply voltage range of 2.5 V to 3.6 V