描述 Description

The CAT9554 is a CMOS device that provides 8-bit parallel input/output port expansion for I2C and SMBus compatible applications. This I/O expander provides a simple solution in applications where additional I/Os are needed: sensors, power switches, LEDs, pushbuttons, and fans. The CAT9554 consist of an input port register, an output port register, a configuration register, a polarity inversion register and an I2C/SMBus-compatible serial interface. Any of the eight I/Os can be configured as an input or output by writing to the configuration register. The system master can invert the CAT9554 input data by writing to the active-high polarity inversion register. The CAT9554 features an active low interrupt output which indicates to the system master that an input state has changed. The device's extended addressing capability allows up to 8 devices to share the same bus. The CAT9554A is identical to the CAT9554 except the fixed part of the I2C slave address is different. This allows up to 16 of devices (eight CAT9554 and eight CAT9554A) to be connected on the same bus.

特性 Features

? 400 kHz I2C Bus Compatible
? 2.3 V to 5.5 V Operation
? Low Standby Current
? 5.0 V Tolerant I/Os
? 8 I/O Pins that Default to Inputs at Power-up
? High Drive Capability
? Individual I/O Configuration
? Polarity Inversion Register
? Active Low Interrupt Output
? Internal Power-on Reset
? No Glitch on Power-up
? Noise Filter on SDA/SCL Inputs
? Cascadable Up to 8 Devices
? Industrial Temperature Range

應用 Application

? Input/output Port Expansion for Extended Addressing Capability
? White Goods (Dishwashers, Washing Machines)
? Handheld Devices (Cell Phones, PDAs, Digital Cameras)
? Data Communications (Routers, Hubs and Servers)

簡介

CAT9554屬于集成電路（IC）的I/O擴展器。由制造生產(chǎn)的CAT9554I/O 擴展器該系列器件可與微控制器、微處理器或類似器件結合使用，目的是增加可用于連接外設的信號連接數(shù)量。典型的工作概念涉及使用串行通信，只需主機設備上的幾根 I/O 線，即可讀/寫擴展器設備上的許多輸入/輸出引腳的狀態(tài)。該技術的通信速度不佳，但連通性較高，最適合快速響應不是很關鍵的應用，例如許多人機界面應用。