Controller puts touch screens through USB ports

Edited by the Electronicstalk editorial team May 7, 2003

A novel single-chip controller is the first to enable integration of any four-, five or eight-wire resistive touch screen with a USB equipped system.

A novel single-chip controller is the first to enable integration of any four-, five or eight-wire resistive touch screen with a USB equipped system.

The UR7HCTS2-USB is part of Semtech's ScreenCoder family, which streamlines integration of CRT or LCD touch screen interfaces by eliminating complex implementation schemes and reducing component costs The device provides high resolution of 1000 points per axis, thereby enabling it to make the precise drawing and signal captures that are required in applications such as electronic point of sale terminals, tablet PCs, PDAs, voting machines, ATMs and interactive kiosks.

The UR7HCTS2-USB controller's extensive compatibility profile maximises the system designer's choices when specifying a manufacturer or type of resistive touch screen for a specific use.

The universal chip also enables a given design to be used among different platforms or successive generations of the same system.

Unlike stand-alone digitiser designs, which relegate the entire control workload to the host processor, the UR7HCTS2-USB integrates the digitiser, controller, and both host system and sensor interfaces, greatly reducing design complexity, development, integration effort, and cost.

The device performs all touch detection, noise filtering, and error elimination tasks, supplying fully processed, stable position data to the host processor via its USB interface.

The UR7HCTS2-USB incorporates unique motion-sensing algorithms that filter out unwanted radio frequency and other signal interference to yield smooth and precise cursor movement.

Other features include a high resistance to RF and other interference sources, touch screen system wake up activation and no requirement for an external ADC.

The device is seamlessly compatible with any operating system that supports the USB HID specification.

With the UR7HCTS2-USB, the touch screen is recognised as a pointer, thus custom or complex software drivers are not required.

Semtech provides a simple calibration routine and driver for the commonly used Windows 98 SE, Me, 2000 or XP systems; this driver is all that is required for final system integration.

Drivers for other operating systems are available through third party vendors.

The device is packaged in a compact 36-pin SSOP.

Samples and evaluation kits are available now from Pulsar Electronics.