Atmel says its maXTouch family of capacitive touchscreen controllers is being targeted at the development of 10 inch touchscreen with zoom and handwriting recognition functions.
The touchscreen controllers, first announced in May are now in production.
The first device in the family, the mXT224, has 224 nodes that allow it to support many simultaneous touches. It will also redraw the screen every 4ms.
The architecture will simultaneously process 224 nodes at 250Hz, while consuming less than 5mW.
According to the supplier, the multi-touch capability means it can "reject unintended touches, stretch/pinch and rotate gestures, handwriting and shape recognition such as face detection on mobile phones, mobile Internet devices and netbook screens surpassing 10 inches."
Another unusual feature is that the device will support the use of a stylus for drawing or signature capture and character recognition. This is the result of a 80:1 signal-to-noise ratio (SNR) and fast refresh rate.
A high SNR is critical for the accurate reporting of adjacent or weak signals, and allows for precise reporting in noisy environments such as products with noise coupled from radio transceivers, LCD displays and battery chargers.
See: Atmel expands royalty-free touch switch library for more MCUs
In the design of the device, Atmel has combined Charge Transfer signal acquisition and XMEGA CPU. The CPU provides signal processing which allows the chip to ignore unintentional activity such as facial touch when on a call with a mobile phone.
The mXT224 integrates Atmel's single-cycle RISC AVR core with 32 registers and two on-chip DSP engines that process the X and Y positions on the touchscreen. An event system and peripheral DMA controller off-load all inter-peripheral communications and data transfer operations from the CPU, freeing it up for post-processing of the sensor image.