Capacitive touch with ultra-low power MCUs assisted by software IP library

May 23, 2013 // By Paul Buckley
Texas Instruments has released a new software library, sensor tuning GUI, design collateral and support for additional microcontrollers (MCU) to ease development of capacitive touch solutions.

With ultra-low power operation at less than 1 µA average current per button, TI’s MSP430 MCUs are a low-energy solution for capacitive touch button, slider, wheel and proximity applications, including portable electronics, household appliances, and accessories.
TI’s open source MSP430 Capacitive Touch Software Library now allows developers to use the MSP430G2xx5 Value Line devices and Wolverine MSP430FR58xx/FR59xx devices for button, slider, wheel and proximity capacitive touch applications. The new devices provide engineers with more options for cost-conscious and low-power applications with capacitive touch. The capacitive touch ecosystem now includes advanced tools to help designers throughout the development process.
The MSP430 Capacitive Touch Pro graphical user interface (GUI) is a new PC-based tool that enables designers to evaluate, diagnose and tune capacitive touch button, slider and wheel designs in real time. This tool charts raw capacitive data from up to ten sensors so developers can visually pinpoint and perform factor analysis easier, resulting in a faster debugging, testing and time-to-market. It features user-configurable ranging, recording and printing options.
You can estimate power consumption for a capacitive touch system even before implementing hardware with TI’s MSP430 Capacitive Touch Power Designer GUI and application note. This GUI simulates the estimated average current draw for capacitive touch systems using select MSP430 MCUs, while users adjust system parameters such as operating voltage, frequency, and number of button and gate times.
Also available are design guides to help developers learn sensor design techniques, reduce power consumption, and improve response times for button, sliders and wheel designs;
Capacitive Touch Sensing, MSP430 Button Gate Time Optimization and Tuning Guide shows developers how to optimise button performance for reduced power consumption, improved response times and scalability to include more buttons.
Capacitive Touch Sensing, MSP430 Slider and Wheel Tuning Guide helps developers lay out sliders and wheels using multiple electrodes and optimise software to provide the most linear representation of raw capacitive data.
Capacitive Touch Sensing, Sensor Design Guide exposes