A ‘Touch’ of Versatility with EVE Custom Touch

9 Apr 2024 – 

Bridgetek are known for bringing innovative solutions to User Interface implementation, such as the Embedded Video Engine (EVE) with its unique approach to adding Graphics, Touch and Audio to existing Microcontroller Units (MCUs).

The new Custom Touch feature introduced on later generations of EVE (BT815 and BT817) is now being added to the capacitive touch versions of the BT88x and FT81x. In this article we’ll explain what Custom Touch is and how it helps you to use a wider range of Capacitive Touch Panels (or CTPs, hereafter referred to as ‘touch panels’) to overcome challenges such as those shown below. This in turn allows EVE’s touch display capabilities to be used in a greater range of applications.

  • Implementing touch without high workload on the MCU
  • Supporting more advanced touch panels to enable a wider range of applications
  • Changing settings on the touch panel to fine-tune touch behaviour
  • Additionally supporting resistive touch panels which have an I2C interface

Introducing Custom Touch

With Custom Touch, you can compile a small code routine tailored to your selected touch panel’s I2C protocol into a binary file, which can be loaded into EVE’s Capacitive Touch Engine. The MCU application can then use the touch features provided by EVE in the same way as it does with the built-in support for capacitive touch panel models. This is ideal for new designs which need a specific touch panel, but also makes it simple to upgrade an existing design.

With Custom Touch, EVE can support a wider range of applications by engaging the EVE's Capacitive Touch Engine, Graphics Engine, Audio Engine

Figure 1 – With Custom Touch, EVE can support a wider range of applications

Recognising that this increasingly popular feature is also highly beneficial to applications which use smaller screens and do not require the full feature set of the BT81x, Bridgetek are now offering Custom Touch on the capacitive versions of the BT88x and FT81x families.

Using Custom Touch to support your chosen touch panel is simple via the free Bridgetek EVE Asset Builder Utility. The Custom Touch code is written in C, allowing easy integration with MCU development tools. Examples are provided for touch panels including Focaltech, Goodix, Ilitek, EETI, Sytronics and Hycon-tek.

EVE Asset Builder makes it easy to develop Custom Touch code

Figure 2 – EVE Asset Builder makes it easy to develop Custom Touch code

Applications enabled by Custom Touch

Graphical touch user interfaces based on EVE are increasingly being used in applications that push the limits of earlier touch panels. It is vital that the touch panel reports touch accurately, without missed or false touches. As improved touch panels become available, their I2C protocol is not always directly compatible with EVE’s built-in touch engine. With Custom Touch, you can add support for:

  • Using enhanced touch panels for better performance in applications with protective glass, and exposure to humidity and liquids and many more etc.
  • Supporting touch panels which have variations in protocol to offer new features (e.g. additional touch button on the bezel)
  • Adjusting parameters such as touch sensitivity by writing touch panel registers over I2C

These features allow the EVE-based design to provide a better user experience and more robustness in applications such as:


Bridgetek developed the Custom Touch feature for BT81x as part of our ongoing product enhancement, based on the way that customers use EVE and the evolution of touch technology. The range of application areas using EVE have diversified significantly, with many being in environments where more advanced touch panel controllers are needed to ensure correct operation and ensure a good user experience.

Bridgetek have therefore added this valuable feature for users of their FT81x and BT88x products. The Capacitive versions of BT88x, FT81x, BT81x all now support both built-in and Custom Touch.

Get in touch with us at marketing@brtchip.com to find out more about EVE and Custom Touch and how it can help you add a graphical touch user interface to your design…