Introducing the NXP PCA9566 16-bit I/O Expander

The PCA9566 from NXP Semiconductors is a robust 16-bit I/O expander, designed to provide additional I/O capabilities to microcontrollers via the two-line bidirectional I²C-bus (Inter-Integrated Circuit). This versatile chip is particularly suitable for applications where I/O pins on a microcontroller are at a premium.

Key Features of the PCA9566

• Expandable I/O Ports: The PCA9566 provides an additional 16 I/O ports, which can be configured as inputs or outputs, allowing for a significant expansion of I/O capabilities without the need to change the microcontroller.
• I²C-bus Interface: It supports both 400 kHz I²C Fast-mode and 100 kHz I²C Standard-mode, ensuring compatibility with a wide range of microcontrollers and systems.
• Interrupt Output: An interrupt output is available and is activated when any input state differs from its corresponding Input Port register state. This is particularly useful for immediate response requirements without the need for constant polling.
• Power Management: The PCA9566 includes built-in power-on reset and features a low standby current, making it suitable for power-sensitive applications.
• Addressing: Up to eight PCA9566 devices can share the same I²C-bus, providing up to 128 additional I/Os. The addresses are set by 3 hardware address pins.
• Compatibility: It is fully compatible with 5 V I²C-bus systems, allowing for easy integration into existing designs.

Applications of PCA9566

The PCA9566 is ideal for a variety of applications, including:

• Server motherboards and industrial PCs where additional I/Os are necessary for system monitoring and control.
• Consumer electronics where it can be used to interface with keypads, buttons, LEDs, and other input/output devices.
• Embedded systems where I/O pin limitations are a concern.

With its flexibility and ease of use, the NXP PCA9566 is an excellent choice for designers looking to expand the I/O capabilities of their microcontroller-based systems without incurring significant additional costs or complexity.