Touchbox (TBX) with controller (CON) and rear-compartment controller (FCON): Touchpad

Depending on the country and special equipment, the controller is also available with integrated touchpad. In this case, the rotary knob has a touch-sensitive surface (touchpad).

The touchpad is an input device for optimized character input and simplified map operation.

A control unit software evaluates the coordinates that were entered using the touchpad. This control unit software is located in the touchbox (TBX) and it is not part of the controller.

Character and gesture recognition occur in the touchbox (TBX). Characters may be letters and numbers. Gestures are scrolling and zooming, for example.

The recognized characters and gestures are transferred to the headunit or rear seat entertainment via CAN bus.

The touchpad has the following technical properties:

• Single-touch and double-touch (recognition of 2 fingers)
• High resolution (up to 100 dpi)
• Quick data transfer rate during scanning (15 ms for an entire scan)

Fig 1: Identifying Rotary Knob, Touchpad And Support Ring

Courtesy of BMW OF NORTH AMERICA, INC.

Signal shape for character recognition: Controller (CON) > K-CAN2 > Touchbox (TBX) > K-CAN2 > Headunit Basis (HU-H)