Overview: Low-Power 16-bit I/O Expander for I2C Bus with Interrupt Product Preview NLA9535, NLA9535C
The NLA9535 and NLA9535C provide 16 bits of General Purpose parallel Input / Output (GPIO) expansion through the I2C-bus / SMBus.
The devices consist of two 8-bit Configuration (Input or Output selection); Input, Output and Polarity Inversion (active-HIGH or active-LOW operation) registers. At power on, all I/Os default to inputs. Each I/O may be configured as either input or output by writing to its corresponding I/O configuration bit. The data for each Input or Output is kept in its corresponding Input or Output register. The Polarity Inversion register may be used to invert the polarity of the read register. All registers can be read by the system controller.
The devices provide an open-drain interrupt output which is activated when any input state differs from its corresponding input port register state. The interrupt output is used to indicate to the system controller that an input state has changed. The power-on reset sets the registers to their default values and initializes the device state machine.
Three hardware pins (AD0, AD1, AD2) are used to configure the I2C-bus target address of the device. Up to 64 devices are allowed to share the same I2C-bus / SMBus.
The NLA9535 is identical to the NLA9555 without the internal I/O pull-up resistors. This significantly reduces power consumption when the I/Os are held LOW.
The NLA9535C is identical to the NLA9535 with high impedance open-drain outputs on the I/O pins.
