Synaptics' sensing devices need sophisticated computation to convert basic analog capacitive and inductive measurements into pleasing, robust pointing behavior. We have developed a proprietary microcontroller design that serves as the core of our sensing chips. A microcontroller is a complete embedded computer with its own program and data memory. Synaptics' microcontrollers use a 16-bit RISC architecture designed specifically for the needs of capacitive and inductive sensors.

In the sensing chips, the microcontroller core is responsible for managing and collecting the analog measurements, compensating for environmental effects such as electrical noise and temperature drift, computing the position and proximity of the pen or finger, detecting motion and tapping gestures, calibrating the Spiral pen, and communicating with the host system using mouse-compatible or other protocols.

Our expertise in chip design allows us to create our own microcontrollers instead of licensing a standard core. This extra effort pays off in many ways. Our chips are smaller and more efficient. They are perfectly adapted to the unusual requirements of our sensors, such as the unique power management issues of inductive sensors and the exposure to electrostatic discharge (ESD) of capacitive sensors. We can adapt our custom architecture to each request. For example, our capacitive sensing chip has a threaded CPU architecture well suited for mouse emulation and a precise RC oscillator to save cost and power. But the needs of inductive sensing called for an event-based architecture and PLL oscillator, so we used those on the inductive sensing chip.

Our chips include EPROM or FLASH program memory for greater flexibility. This, combined with our powerful, general-purpose microcontroller core allows us to apply our technology to a wide variety of products and markets.