Port expanders make more of I2C comms

Three new I2C port expanders store all user settings in nonvolatile memory, eliminating the need to reconfigure the device after each power-up.

Cypress Semiconductor has introduced three new I2C port expanders that store all user settings in nonvolatile memory, eliminating the need to reconfigure the device after each power-up.

The devices deliver up to 60 input/outputs (I/Os) - the industry's highest total - and offer more pulse-width modulators (PWMs) and more I2C-accessible EEPROM memory than competing devices.

They are well suited for a wide range of applications, including computing, communications, and industrial.

The new devices are optimised for port expansion without the need for user programming.

Cypress's new I2C port expanders use a proprietary "extendable soft addressing" algorithm that allows flexible I2C configuration of up to 127 devices addresses per bus.

This feature enables control of up to thousands of bidirectional I/Os in any application.

The devices are based on Cypress's popular and flexible PSoC programmable system-on-chip architecture, but do not require user programming, delivering an optimised solution for port expansion.

"Our solution offers more I/Os, more memory and better functionality than competing products, at the lowest price per I/O on the market", said Steve Gerber, Director of Marketing for Cypress's PSoC Business Unit.

The three new devices offer users varying amounts of I/Os, I2C-accessible EEPROM and PWM sources: the CY8C9520 has 20 expansion I/Os, 3Kbyte of EEPROM and four PWM sources; the CY8C9540 has 40 expansion I/Os, 11Kbyte of EEPROM and eight PWM sources; and the CY8C9560 has 60 expansion I/Os, 27Kbyte of EEPROM and 16 PWM sources.

Cypress's new port expanders employ the industry-standard I2C interface, offering easy migration from existing designs.

The devices are offered in industrial temperature range of -40 to +85C, with operating voltage ranging from 3.0 to 5.25V.

The new products include an optional EEPROM write disable pin input, an interrupt output that indicates input pin level and PWM state changes, and internal power-on reset.

In addition, every I/O can connect to a PWM, and a single register command stores current configuration as nonvolatile defaults.

All three Cypress port expanders are available in production volumes today.

The CY8C9520 is offered in a 28-pin SSOP package, the CY8C9540 comes in a 48-pin SSOP and the CY8C9560 is offered in a 100-pin TQFP package.

The CY8C9520 is priced at $0.99 in high volumes.

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