Giving Touchscreen Technology That Personal Feel

 

Why Atmel maXTouch Microcontrollers Lead the Market

Atmel® maXTouch® microcontrollers are the culmination of touchscreen engineering efforts that span more than 15 years. Atmel development teams have produced an optimal and scalable capacitive touchscreen architecture that is without peer in sensing the user’s input.

 

Unlimited Touch, Limitless Possibilities

Unlimited-touch capability opens up a range of new possibilities for interface designers. By recognizing as many touches as people have fingers, the technology can support a variety of multitouch gestures anywhere on the surface. But just as important, unlimited touch makes it possible for the device to detect and ignore unintended touches, such as the pressure of the user’s ear, cheek, or hand grip.

 

Fast Response Improves the Experience

Scanning an entire screen takes only a few milliseconds, enabling the interface to keep up with the user's motions in real time. This allows the device to support advanced applications such as games, as well as handwriting recognition. maXTouch technology has the flexibility to dynamically adjust the scan frequency up or down as needed to conserve power.

 

A Precise Touch Is a Sensitive Touch

Faster scan rates allow for more sensor nodes and grid lines across the interface than competing touch products support. With a two-touch adjacency of less than 10 mm on a 4.3-inch (10.9 cm) touchscreen, the ICs can detect close-together touches precisely and unambiguously. The technology is also good at dealing with repeated touches on a small area (such as a phone icon) and different angles of touch. Sensitivity is so precise that users can get good results with a fingernail, a stylus, or even with gloves on.

 

Highly Configurable and Flexible

The chips are designed to meet the requirements of a whole new generation of innovative products and interfaces, with few constraints on sensor implementation. Built-in gesture reporting enables advanced interface features — from executing flicks and zooms to drawing characters and playing games. The designer can configure and change settings, such as touch sensitivity, how many touches are reported, and display resolution. The technology can accommodate screens up to 15.6 inches (39.6 cm) in size.

 

Powerful, But Not Power Hungry

Atmel touchscreen microcontrollers are some of the lowest power consumers in the industry. A signal acquisition method that allows all Y lines in a grid to be scanned in parallel is so efficient that the chip can spend most of the time in low-power sleep mode. This pulls less power from mobile device batteries and lets users go longer without charges.

 

Small Footprint, Low Component Costs

Combining Atmel patented Charge Transfer and XMEGA™ technologies, the touchscreen ICs feature a well-optimized architecture that occupies minimal space on a circuit board. A high level of integration — few external passive components are needed — saves on component costs.

 

Rugged and Noise Tolerant

Robust and resilient, the maXTouch microprocessors can handle extreme temperatures and dusty or wet conditions. This makes them ideal for outdoor or industrial applications. In addition to effective internal noise suppressing techniques, maXTouch technology also features frequency hopping to avoid noisy frequency bands. By changing the frequency of the signals used to drive each sensor, the signal acquisition takes place in frequency bands with less noise.

 

Mutual Capacitance for Greater Accuracy

There are two basic ways of arranging and measuring the change in capacitance on a projected capacitance touchscreen: self-capacitance and mutual capacitance. With self-capacitance, an entire row or column of touch points is measured for change. This results in ambiguity if the user touches two places on the same line. One of the touches is often not detected. On the other hand, Atmel maXTouch technology uses a more advanced mutual capacitance method in which transmit and receive electrodes are placed in an orthogonal matrix — essentially an array of mini-touchscreens. Because the capacitive coupling at each point in the matrix can be measured independently, there is no ambiguity in the reported coordinates for multiple touches. This results in greater accuracy and a better user experience.