The TXE81XX-Q1 devices provide general purpose parallel input/output (I/O) expansion for the four wire Serial Peripheral Interface (SPI) protocol and is designed for 1.65V to 5.5V VCC operation. The device supports 10MHz from 3.3V to 5.5V and 5MHz from 1.65V to 5.5V. I/O expanders, such as the TXE81XX-Q1, provide a simple solution when additional I/Os are needed for switches, sensors, push-buttons, LEDs, and fans. The TXE81XX-Q1 devices have I/O ports, which include additional features designed to enhance the I/O performance in terms of speed, power consumption, and flexibility. The additional features are: enable/disable pull-up and pull-down resistors, latchable inputs, maskable interrupt, interrupt status register, programmable open-drain or push-pull outputs, and a fail-safe register mode which is enabled by the FAIL-SAFE pin.