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Touch controller adds LED, GPIO functions

Posted: 09 Jul 2008 ?? ?Print Version ?Bookmark and Share

Keywords:touch controller chip? LED control? GPIO functions? multimedia HMI controller?

Atmel Corp. has announced the AT42QT2160, a touch controller IC combining touch key and touch slider functions in a single device. The AT42QT2160 can control up to 16 individual touch keys with a slider comprising between 2 and 8 of the touch key channels. In addition, the chip can also control up to 11 LEDs through a PWM output function that is controlled by the host, eliminating the need for an external LED controller.

With this combination of functions, this device is suited for use as a multimedia HMI controller in mobile phones and consumer applications, such as personal media players, where it saves space, minimizes design time and allows the designer creative flexibility in laying out control keys. With its wide voltage range (1.8V to 5.5Vdc) and low power requirements, it is well suited for other battery-driven applications, such as digital still cameras, PDAs or handheld gaming devices.

The AT42QT2160 uses Quantum Research Group's (acquired by Atmel in March) patented charge-transfer technology. This provides robust and reliable performance, high immunity to EMI through spread-spectrum modulation and filtering algorithms, calibration of the device over life and user-defined sensitivity thresholds for individual keys. An additional patented function, adjacent key suppression (AKS), intelligently suppresses signals present from nearby keys so that only intended keys register a touch.

The AT42QT2160 has three GPIOs with PWM capability and a further eight shared ports that provide additional standard outputs for the host without adding cost or using an extra I/O expansion device with PWM capability. Host configurability is achieved via a two-wire interface (I?C compatible). To save system power, the chip provides a system multi-input wake-up (MIWU) function. This can trigger a reaction from the host or other system components via the two-wire interface, or using a dedicated output pin, when pre-defined input signals levels are reached. Touch button sensor electrodes, of arbitrary size (>6mm x 6mm) and shape, are usually formed from copper pads on the PCB or a flexible circuit. The touch surface can be made from glass up to 3mm in thickness or plastic, up to 2.5mm thick.

"This is the first of many new products that we will launch in the next year as we accelerate our R&D in touch technology to capitalize on one of the fastest growing embedded applications," said Peter Jones, managing director of Atmel's MCU business unit. "We expect to see up to 60 models of mobile phones adopting our technology over the next 12 months and the increasing use of touch controls in everything from laptop PCs to consumer electronics. It's a very exciting time to be in this business."

The AT42QT2160 is the latest addition to Atmel's comprehensive range of capacitive touch controllers based on Quantum Research Group's charge-transfer technology. These include QTouch controllers for single and multiple touch buttons, touch sliders and touch wheels, together with QMatrix devices for higher density matrix key panels.

Samples of the AT42QT2160 IC are available now in a 28-pin, 4mm x 4mm QFN package. Pricing for the part is 98 cents each for quantities of 100ku per year. A demonstration board for development support is also available.

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