By Interlink Electronics 49
The Interlink VersaPad is a versatile touchpad module intended for integration by OEMs into laptops, military and rugged computers, panel PCs, and medical devices. With smoothness and sensitivity internally enhanced by true pressure measurement, it offers all customary mouse functions: mousing, tapping, dragging, and scrolling. The module's tough, moisture, and grime-resistant surface can be used with a finger or stylus, even in wet or dirty environments. Plus, it operates over an extended temperature range of -20°C to +60°C.
The module is fully USB 2.0 compliant and enumerates utilizing native O/S drivers as a HID mouse with left-, right-, and center-click capability. The mouse can also be suspended by the host, but the mouse cannot wake the host from suspend mode. No features of the mouse are settable by the host via USB. The USB VersaPad enumerates as a standard three-button HID-compliant mouse and requires no additional driver. In the future, Interlink may provide a driver that adds additional functionality and customization possibilities to the Windows standard mouse behavior.
The module is a resistive, 4-wire X-Y touchpad measured by a microcontroller. When not touched, the touchpad appears to the microcontroller as an open switch. On a touch event, the processor detects this 'switch closure' and begins to evaluate the touchpad through a series of measurements. The processor 'oversamples' the touchpad to facilitate filtering and processing of the mouse report.