Codec adds touch-screen control to PDA

The WM9705 codec has been used as an enabling device in the Treo 600 smartphone from palmOne.

The Wolfson WM9705 codec has been used as an enabling device in the Treo 600 smartphone from palmOne.

The Treo 600 is the acclaimed, cutting-edge mobile phone combining PDA, phone and messaging functionality.

Wolfson's WM9705 codec integrates a high performance audio codec with a four-wire touch screen controller, complete with on-chip screen drivers.

Pen-down detection features and pressure measurement capabilities are also provided delivering a convergence of audio and PDA facilities.

The WM9705 allows audio, touch screen data, software interrupts, control address and data information to be transferred to and from a processor using a single four-wire bidirectional AC link interface.

This unique interface reduces device pin-count and dramatically reduces the software overhead on the processor to manage all the data.

"One of the biggest reasons for selecting the WM9705 was the touch panel capability, combined with the audio capabilities, that allowed us to eliminate an additional component, lowering both cost and power consumption", said Mostafa Kashi Senior Hardware Development Engineer for palmOne.

"We have little time to decide what components to include in our designs, so the benefits of any product have to be obvious.

The capabilities of the WM9705 made it a winner for us and we may be looking to work with Wolfson technology on future designs".

The audio section of the WM9705 provides full-duplex 18bit codec functions and supports variable sample rates from 8 to 48Ksample/s with high signal to noise ratio.

Additional audio features include 3D sound enhancement, line-level outputs and stereo-buffered headphone outputs.

The WM9705 also features microphone and headphone switching capabilities that make it a good choice for mobile telephony applications.

"Wolfson foresaw the needs of modern, personal, handheld communications devices when incorporating the AC97 audio standard with advanced features such as a stereo headphone driver and touch screen controller", said David Milne, CEO of Wolfson Microelectronics.

"This combination of functionality should be a boon to the next generation of portable information devices that require both advanced multimedia functionality and touch screen capability for easy user navigation".

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