CONFIGURATION REGISTERS

DESCRIPTION

The UTC UCA9555 is a low standby current I/O expansion with

24-pins,which can provide 16-bit general parallel input/output

expansion for I2C bus. UCA9555 has three hardware address bits,

These three hardware address bits allow up to eight devices to

share the same I2C-bus.

The UTC UCA9555 has power-on reset function. When

power-on and reaching a certain voltage, the internal state

machine will be initialized and the register will be set to the default

value. The open-break interrupt output of UCA9555 will be

activated when the input state is different from its corresponding

input port register state and will send an indication to the system.

The UTC UCA9555 has 16 I/O ports, which are divided into two

groups, each group has 8 I/O ports. These two groups of I/O ports

can be used as input ports or output ports. UTC UCA9555 is used

for push buttons, fans, LEDs, sensors, etc. when these devices

require additional I/O, UTC UCA9555 can provide a solution. In

addition, it also has the function of polarity inversion, which can be

selected through the register. The system master can enables the

corresponding register by writing the corresponding byte to realize

the corresponding function.

FEATURES

* Operating voltage is 2.3V to 5.5V

* The standby current is low

* SCL/SDA has an input filter

* Power-on reset

* 5 V tolerant I/Os

* The interrupt output is low

* Polarity Inversion register

* Address by Three Hardware Address Pins for Use of up to Eight Devices

* 16 I/O pins which default to 16 inputs

* 400kHz Fast-mode I²C-bus