Touch controller enables touchpad designs in car center stacks

July 15, 2013 // By Christoph Hammerschmidt
The center stack in cars has a double role: It contains the user interface for many functions such as climate control or infotainment system as well as the associated electronic devices. This where Atmel Corp. aims at with its new maXTouch controller product family. The devices enable single-layer shieldless designs in center stacks, navigation systems, radio interfaces or rear seat entertainment systems.

The maXTouch family comprises two members: The mXT336S is optimized for 7-inch touchscreens, while the mXT224S targets smaller touchscreens and touchpads. Both devices strengthen Atmel's position as a supplier to consumer, industrial and automotive applications. The new touch devices are AEC-Q100-compliant and fully automotive qualified.

They offer superior performance, multitouch functionality, faster response time than their predecessors, more precise touches, robust operation and lower power consumption. The new mXT336S and mXT224S devices also provide dedicated embedded functionality that meet current automotive design requirements.

Dedicated firmware and a high signal-to-noise ratio makes these devices suited for very noisy environments. Since only a high signal-to-noise ratio enables detection of touches with a "gloved" finger, the devices provide full support for gloved hand operation on automotive touchscreens.

One key requirement for automotive designs is the support for shieldless sensors. "Conventional touch controllers are unable to handle LCD noise, so an additional shield layer is required to prevent noise coupling," said Stephan Thaler, Atmel Marketing Director for Automotive Touch Products. "Thanks to the superior noise handling and filtering capabilities of our new devices, shields are no longer required, and designers can use single-layer sensors instead of dual or triple layers, which are typical in many current applications. By eliminating an additional layer, designers have a thinner stack which reduces the overall system complexity, lowering the overall cost and power consumption, and resulting in higher product yields during production."

The mXT336S/mXT224S devices support touch detection, up to 10 simultaneous touches, touch size reporting, single- and dual-touch gesture calculation, communication of X/Y positions, gesture support, and the ability to eliminate unintended touches. Users can perform multi-touch gestures (pinch, stretch, etc.), while unintended touches are rejected, such as a resting hand on the screen. All these key features bring the smartphone experience into contemporary cars.

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