ST solution ups mobile platform system resources

STMicroelectronics (ST) has unveiled the new Xpander Logic family to help customers overcome the limited number of I/O ports in MCU and microprocessor-based embedded systems.

According to the company, any existing or additional I/O-intensive tasks on the CPU can be now reassigned to the Xpander Logic IC that operates off ultralow power and comes in a small package, making it suitable for portable multimedia devices such as mobile phones, smartphones and personal digital assistants.

Intelligent functions
The Xpander Logic family allows the existing system processor to use a wide range of intelligent functions through a standard and high-speed I2C serial peripheral interface. These intelligent features include a keypad controller, supporting 96 keys maximum, and a pulse-width modulation controller, to adjust the brightness of the LEDs in addition to performing sophisticated brightness patterns.

In addition, the Xpander Logic family offers a 3-wire rotating-wheel controller that supports the rotating wheel interface in portable electronics by detecting the motion of the wheel and providing monitoring/buffering features. The family also integrates ADC and DAC, allowing the host system to implement a wide range of mixed-signal features while providing an automatic dimming unit that lets the ambient light sensor control a backlight unit without CPU intervention.

Expanded resources, extended battery life
ST said that all these features were achieved through a minimum change on the existing microprocessor or MCU firmware, providing a flexible and cost-competitive solution able to expand system resources compared to the complex implementation of larger and more expensive CPU or programmable logic devices in the embedded system.

Another feature of the Xpander Logic family is the high optimization for micro-power operation and the advanced power-management support that helps modern portable systems preserve and extend battery life.

Pricing and availability
Currently in production, the devices are housed in small packages. The Xpander Logic STMPE2401 provides all the above-mentioned intelligent functions in a microTFBGA36 package, while the STMPE801 performs the basic I/O expander function in a QFN16 package. The STMPE2401 and STMPE801 cost $1.5 and 80 cents, respectively, in 100,000-unit quantities.