New Industry Products

Dallas Semiconductor Unveils New DS1680 Portable System Controller

October 08, 2000 by Jeff Shepard

Dallas Semiconductor Corp. (Dallas, TX) launched the DS1680 portable system controller for touch-screen devices. The DS1680 simplifies board setup, cuts manufacturing costs, saves space and reduces chip count in instruments utilizing touch-screen technology, and is the first chip to integrate a clock/calendar, power monitor, watchdog, NV ram control and touch-screen control circuits, according to the company.

The DS1680 can be used in PDAs; POS systems; Internet appliances; and interactive detectors, sensors and testers.

Jim Waldron, product manager, said, "Until now, touch-screen control circuits have been available separately or in less efficient combinations. For example, some designs build touch-screen control into the system processor, then use external components for the rest of the monitoring and clock functions. The DS1680 is the first to condense the complete set of time and control functions into one chip, simultaneously unburdening the processor and preserving system resources."

The DS1680 is optimized for hand-held instruments that utilize four-wire resistive-touch screens, which consist of two resistive plates separated by a small gap. The touch of a pen or stylus causes the two plates to come into contact at the exact position of the touch, setting off a voltage drop. Using an on-chip a/d converter, the DS1680 derives the x-y plane coordinates of the contact position, and then feeds the information to the processor.

Along with touch-screen control, the DS1680 incorporates multi-faceted circuitry necessary for processor-driven systems. Power-monitoring circuits protect operations by halting the processor during power failure and automatically restarting it on power return. A push-button input allows for external power control. To ensure that software is operating reliably, a watchdog circuit monitors processor activity and initiates a reset after a specific time-out.

The DS1680 portable system controller is available in versions for 3.3V and 5V supplies. Both versions are packaged in a 44-pin MQFP, priced at $5.04 in quantities of 1,000. The DS1680 is sampling now with full production expected in the first quarter of 2001.