Touchpad 4 Click as its foundation uses the IQS7211A, a tiny trackpad controller designed for multitouch applications using a projected capacitance touch panel from Azoteq. The IQS7211A is part of Azoteq's latest range of ProxFusion combination sensors, a multi-sensor technology that offers combinations of capacitive sensing, Hall-effect, inductive, and temperature sensing on a single integrated circuit. It allows users to control a trackpad of up to 32-channels and offers high resolution and fast response, low power consumption, and long-term activation supported by environmental tracking. It is also characterized by embedded gesture engine recognition for simple gestures (tap, swipes, hold) and built-in noise detection and filtering.

On the Touchpad 4 Click front side, there is a clearly defined field that represents a touchpad area. This area is a matrix of conductive electrodes on the PCB, electrically isolated from each other, arranged as rows and columns of X and Y. An electrode consists of multiple diamond-shaped elements, each connected to the next with a conductive neck.

The controller uses the principle of projected capacitance charge transfer on the touchpad area. When a conductive object such as a human finger approaches the sense plate, it will decrease the detected capacitance. Observing the measured results at various sensing points on the touchpad area enables the controller to determine proximity/hover detection and contact (touch) detection on all channels and accurately determine the coordinates on the touch area.

Touchpad 4 Click communicates with MCU using a standard I2C 2-Wire interface, with a clock frequency up to 1MHz in the Fast Mode. An additional ready signal, routed on the INT pin of the mikroBUS™ socket, is added, which indicates when the communication window is available. Thus, it is optimal for the response rate to use the INT pin as a communication trigger. Alongside this pin, this Click board™ has a Reset feature routed to the RST pin on the mikroBUS™ socket, which with a low logic level puts the module into a Reset state, and with a high level operates module normally.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.