Push buttons are out and touch panels are in for an increasing number of consumer, industrial, medical and automotive designs. Freescale Semiconductor, a leading designer and manufacturer of sensor devices, is helping redefine touch-sensitive user interfaces by introducing a pair of next-generation capacitive sensor controllers and a proximity sensing software solution that works with hundreds of Freescale microcontrollers (MCUs).
Touch-sensitive controls are rapidly supplanting mechanical buttons, sliders and switches by providing a flexible, reliable and cost-effective user interface alternative. Touch sensing technology helps designers unleash their creativity in developing intuitive touch-based rotary wheel and linear slider interfaces with the ability to hide or illuminate buttons and “morph” touchpad patterns. Touch panels are sealed from spills and dust, have no moving parts to wear out, and present a clean, contemporary and easy-to-use interface for a wide range of consumer and industrial products. For these reasons, touch-based controls are becoming the user interface of choice for designers of cell phones, portable media players, home appliances, remote controls, electronic games, PC peripherals, home entertainment products and industrial control equipment.
Freescale is helping reduce the cost and complexity of developing touch-based user interface applications by providing designers with two flexible options:
A choice of rotary and touchpad capacitive sensor controllers combined with full-featured touch-sensing algorithms for complex interface designs that require calibration and multiplexing capabilities
Complimentary proximity sensing software derived from the full-featured algorithm designed to enable easy integration of touch sensing technology into cost-sensitive control applications using Freescale’s 8-bit S08 and 32-bit ColdFire® V1 MCUs
“Freescale’s approach to touch sensor technology will almost certainly drive more innovative touch-based interface options for end-users,” said Marlene Bourne, principal analyst with Bourne Research. “Freescale has not only created a cost-effective solution that gives developers incredible flexibility and freedom of choice, but with exceptionally high accuracy and precision for traditional industrial sensing applications, this advanced alternative will make traditional push-button-switch user interfaces a thing of the past.”
Cutting-edge proximity sensor controller portfolio
Freescale’s MPR083 and MPR084 capacitive touch sensor controllers are designed to detect the presence of objects without relying on physical contact. For example, the controllers can be used in the front panel of a washing machine to replace mechanical knobs and push buttons. Users simply bring their fingers in proximity to an indicated command on the panel, and the washing machine begins the requested function.
The MPR083 and MPR084 devices support configurable real-time auto calibration. Self-calibration is engineered to perform automatically at initial device start up and during run time. The sensor controllers also support multiple electrodes, enabling one controller to support multiple applications. By multiplexing the electrodes, a single sensor controller can be used for detection at multiple touch points. For example, the sensor controller can be used to manage multiple electrode configurations for touch pads, sliders, rotary positions and mechanical keys. This multiplexing capability helps reduce system cost, component count and design complexity.
The MPR083 controller is ideal for rotary interface applications, and the MPR084 is well suited for touch panel control applications. Both controllers have a common pin-out, which simplifies management of control panels, switch replacements, rotary and linear sliders, and touch pad implementations. Both devices use a digital output I2C interface for system communications. The voltage operation range is 1.8V to 3.6V, which is ideal for consumer electronics.
Adding touch capabilities to cost-effective MCUs
To help lower the cost of entry for touch sensor-based designs and speed the adoption of touch sensing technology, Freescale offers complimentary proximity sensing software designed to run on all Freescale 8-bit S08 and 32-bit ColdFire V1 MCUs, encompassing hundreds of device options. The software provides a cost-effective, source-code solution for design engineers who want to integrate touch sensing capability for up to 32 electrodes into their existing S08 and ColdFire V1 MCU designs.
The proximity sensing software is available with an affordable add-on development board designed to help developers get their applications up and running quickly and at minimal cost. By purchasing a touch sensing add-on board, developers can easily turn their existing MCU development kits into touch sensing application development kits. This approach enables customers to benefit from an additional return on their investment in Freescale’s 8- and 32-bit MCUs.
“Freescale’s proximity sensing software enables embedded developers to ‘just add touch’ to their cost-sensitive 8- and 32-bit designs,” said Demetre Kondylis, vice president and general manager of Freescale’s Sensor and Actuator Solutions Division. “With our software, designers can take advantage of advanced touch sensing technology quickly, easily and within budget, and it helps make the migration from older mechanical push-button interfaces to touch sensors fast, reliable and cost effective.”
MPR083 and MPR084 controller features
- Supports 8-position rotary (MPR083) and 8 touch pads (MPR084)
- 1.8V to 3.6V operation
- 150 micro amps average supply current (all touch pads being monitored)
- 1 micro amps standby current
- Proprietary false touch rejection technology
- Ongoing pad analysis and detection not reset by EMI events
- Sounder drive to simulate mechanical key clicks for audible feedback
- Digital output (I2C with custom addressing)
- 16-pin QFN and TSSOP packages
- -40°C to +85°C operating temperature range
Complimentary proximity sensing software features
- NRE/royalty-free software solution, with source code built on CodeWarrior software
- Eight electrodes implemented in the code base; capable of supporting up to 32 electrodes
- Enables use and configuration of any available GPIO pin as an electrode input
- Programmable sampling period
- Adjustable touch threshold setting
- Simple averaging function as basic low-pass filter
- Buzzer sound feedback on electrode touch
- Wide variety of hardware options
- Compatible with hundreds of S08 and ColdFire V1 MCU products
- 1.8V–5.0V operation (MCU dependent)
- Numerous packages options (MCU dependent)
- -40°C to +85°C operating temperature
Pricing and availability
The suggested resale price for the MPR083 and MPR084 touch sensor controllers in 10,000-piece quantities is $1.07 (USD).
Freescale also offers several evaluation kits to help reduce development time and cost. The KITMPR083EVM and KITMPR084EVM kits for MPR08X-based development are available at a suggested resale price of $99 (USD) each. The KITPROXIMITYEVM add-on evaluation kit is available for S08 and ColdFire MCU-based development.
The MPR083 and MPR084 devices, evaluation kits and proximity software add-on kit are planned to be available in January 2008.
About Freescale Semiconductor
Freescale Semiconductor is a global leader in the design and manufacture of embedded semiconductors for the automotive, consumer, industrial, networking and wireless markets. The privately held company is based in Austin, Texas, and has design, research and development, manufacturing or sales operations in more than 30 countries. Freescale is one of the world’s largest semiconductor companies with 2006 sales of $6.4 billion (USD).
Freescale and the Freescale logo are trademarks or registered trademarks of Freescale Semiconductor, Inc. in the U.S. and other countries.