Noise-resistant capacitive touch MCU has IEC 61000-4-6 certification

November 13, 2015 // By Graham Prophet
Texas Instruments' MSP430 FRAM microcontrollers (MCUs) gain “CapTIvate” technology, that TI positions as the lowest-power capacitive touch MCUs available. These MCUs with have comprehensive hardware and software features for the most reliable performance in noise-challenged applications, including electronic access controls, appliances, personal electronics, and industrial control panels.

Expanding TI’s 16-bit ultra-low-power FRAM (ferroelectric memory) MCU portfolio, the MSP430FR2633 MCU with CapTIvate technology enables designers “of all skill levels” to build robust human-machine interfaces (HMI) with capacitive buttons, sliders, wheels or proximity (BSWP) sensors. It also enables multi-touch designs with plastic, glass and metal overlays of various thicknesses. Designers can quickly create solutions with the CapTIvate Design Centre, a graphical user interface (GUI) that allows developers to drag and drop sensors for quick system configuration and start tuning for performance in five minutes or less.

Wake-on-touch hardware on chip can continuously scan up to four electrodes while the CPU is shut down, enabling up to 15 years of operation on a single coin cell battery with current consumption of 0.9 µA per button in sleep mode. These ultra-low-power MCUs with Ferroelectric Random Access Memory (FRAM) feature non-volatile memory with greater endurance and 100 times faster write speeds, enabling systems to wake from the lowest power standby modes in a fraction of the time. FRAM also provides the option of saving and restoring button state in the event of power failure without the use of space-consuming backup batteries.

MSP430FR2633 MCUs with CapTIvate offer developers a great deal of design flexibility without compromises, TI adds. In an access control system, a proximity sensor may be needed to illuminate the screen and a large matrix of buttons to support user input. Self-capacitance provides higher sensitivity for proximity sensing, while mutual-capacitance allows for a large number of tightly packed buttons with lower crosstalk. CapTIvate technology provides flexibility to simultaneously support self-capacitance and mutual capacitance for an enhanced system solution. The MSP430FR2633 MCU can support 16 button self-capacitance and 64 button mutual-capacitance modes.

CapTIvate provides hardware features such as a dedicated voltage regulator, frequency hopping, zero crossing synchronisation and signal processing algorithms that prevent false detects in noisy environments. Spread spectrum clocking lowers electromagnetic radiation, reducing emissions to system circuitry.

Features include;