If you, as an engineer, have been challenged by your marketing team to update your applications’ user interface design from a traditional mechanical button implementation to a new state-of-the-art capacitive touch system, then you might want to look into the RX130 Touch Key solution, which was just recently launched by Renesas.

Renesas offers, not only the MCU itself but everything you need for your own board development, such as a board circuit diagram, application code and PCB layout recommendations. The RX130 Touch Solution kit can be used as a demonstrator for your new applications’ user interface with its multiple adapter boards which include slider, wheels and both mutual and self-capacitance buttons.

The 32-bit RX130 MCU

The 32-bit MCU RX130 Group integrates a built-in max. 36-channel Capacitive Touch Sensing Unit (CTSU) IP block. The CTSU uses an improved detection method compared to previous products which provide for vastly improved noise immunity and sensitivity.

Its use of spread spectrum technology in the detection process has resulted in high-performance touch detection allowing it to be used with a wide variety of overlay materials such as wood as well as the typical acrylic or glass. The RX130 mutual capacitance touch detection feature is an ideal fit to consumer electronics products that are used in wet environments such as in the kitchen or bathroom. The RX130 Group includes built-in functional safety hardware and can easily support the IEC/UL60730 safety standard for consumer electronics. The RX130 operates at a maximum voltage of up to 5.5 V, so is suitable for applications such as home appliances (washing machine, IH cooking) requiring touch panel functionality.

The RX130 Touch Solution is supported by the Workbench6 touch evaluation tool which can be downloaded from the Renesas website. Workbench6 is a PC-based GUI which provides simple development of your capacitive touch interface and contributes to reduced development workload. Workbench6 allows simple setup and calibration of the capacitive touch interface, automatic C/C++ project generation and real-time debugging tools which contributes to the shorter development time.

The RX130 is supported by three flavours of evaluation boards:

• Renesas Starter Kit (RSK) 
  Allows a full evaluation of the RX130 including a
  standalone E2 on-chip debugger and including touch keys and sliders (self-capacitive type). RS Stock number (173-3528)
• Target Board for RX130
  Lowest price point, to allow engaged with RX MCU with at no barrier. The kit even stands customers first evaluation, due to integrated E2 Lite OB debugger.
• Capacitive Touch Evaluation System for RX130
  Renesas Solution Starter Kit - for dedicated capacitive touch key evaluation. Evaluates various touch functions:
  • Button, slider, wheel, matrix key, proximity sensor
  • Simple prototyping
  • Use as a reference when designing boards or software
  • RS Stock number (172-9135)

In the following chapter, I will look in more detail into the Capacitive Touch Evaluation System for RX130 as it gives a wider choice of capacitive touch interface options compared to the RSK.

In addition to capacitive sensing evaluation, engineers developing their system can enjoy the benefits of Renesas’ Firmware Integration Technology (FIT). FIT is a completely new concept that emphasizes the simplification of embedding of peripheral function module drivers and improvement of portability between RX microcontrollers with the aim of lightening the burden of program development and software resource management in software development using the RX Family.

The Touch Solution Kit

The Touch Solution Kit shows the capabilities of the RX130 MCU and makes it easy for users to evaluate touch solutions offered by Renesas. The kit includes two sensor evaluation boards which allow them to quickly evaluate whether their application interface would benefit from either self-capacitance buttons, sliders or wheels, mutual capacitance buttons (for water resistance) or proximity detection.

Other features such as ease of prototyping and debugging using the accompanying tools (Workbench6 and e2Studio) provide for fast time to market of a new state of the art modern interface for the user's application.

Benefits:

• Provides fast capacitive touch interface demonstrations to marketing for end product evaluation
• Automatic C/C++ Project generation provides functional bare metal firmware ready for fast application development (No MCU bare metal learning curve)
• Visual capacitive sensor operating parameters in real-time provide confidence in setup and tuning.
• Comprehensive documentation provides for a confident initial printed circuit board layout resulting in lower costs due to zero prototype re-spins
  
  

The Workbench

For a quick and efficient Touch Solution development, a suitable development environment is required to support the journey of your design cycle. This is provided in the Touch Solution Kit in the form of the Workbench6 PC-Based GUI tool in conjunction with the e2Studio IDE.

The Workbench6 provides a “First Step Guide” workflow which takes the developer on a step-by-step journey through the design process. The process includes HMI design (number of buttons, slider etc), printed circuit board performance testing, touch calibration and final C/C++ project creation. With the project created and running on the target hardware, further real-time tuning and monitoring tools are provided to ensure a final robust and reliable capacitive touch interface in the application.

Benefits:

• Fast development due to fixed “First Step Guide” workflow
• Instant C/C++ Project running on your hardware
• FIT compliant project simplifies addition of RX family peripheral drivers and middleware
• Monitoring tools provide real-time interface performance verification resulting in high pre-production design confidence
  
  

Free Middleware and Driver

To complement the automatic C/C++ Project creation from Workbench6, you will be pleased to know that further programming support is provided by the Peripheral Code Generator tool. This is a free tool that can be downloaded from the Renesas website and via a simple GUI interface you can configure additional hardware peripherals (UART, IIC, ADC, DAC etc) and create source code based on your choices. This source code can then be easily integrated with the capacitive touch firmware created by Workbench6.

However, with more complex projects, it will be necessary to write code yourself. To facilitate the effort, the Firmware Integration Technology (FIT) provides numerous libraries including USB and Ethernet stacks which can also be easily integrated with the capacitive touch solution firmware.

Touch Solution Forum

If you are interested in more detail about the Touch Solution, please visit the popular Renesas Rulz forum. The forum includes a CapTouch category which includes a large database of questions and answers relating to capacitive touch technology. This support resource will help with your understanding of capacitive sensing and the Renesas implementation of the technology. The resulting improvement in your design cycle with further enhance your capacitive touch application experience.

So please have a look at https://renesasrulz.com/capacitive-touch-cap-touch/

Registration and the usage of the RenesasRulz forum is free of charge.

Conclusion

The Touch Solution Kit, as well as the RX130 MCU, is the ideal solution for your Capacitive Touch application as it covers all the aspects of a design process. You will very quickly be up and running with a capacitive touch demonstrator for your marketing team to evaluate and confidently get up to speed on important aspects of a capacitive touch design resulting in a fast development time for your final production quality application. Please remember those Touch Solution Kit key features to make your day :

• An assortment of sensors to evaluate (buttons, sliders, wheels and proximity)
• Automatically generated, fully functional C/C++ Project for your capacitive touch application
• Quick start guide gets you up and running instantly
• Free of charge C Compiler (limited to 128kB Flash code after 60 days)
• Free Middleware and peripheral drivers
• Free Touch Development environment (Workbench6)
• Free Eclipse-based IDE (e2Studio)
• Comprehensive documentation

Find out more...

Have a nice and successful engineering day!