Push Button Switch Has Built-In TFT Colour Graphics Display

17th May 2009

ES Admin

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Foremost Electronics has introduced a new man-machine interface solution. The TFT128 ScreenKey is a push button switch with a built-in full colour, high resolution TFT graphics display. The display is backlit by a white LED and the integrated TFT LCD display has a resolution of 128 x 128 pixels, where each pixel colour may be chosen from a palette of 65,536 colours.

The TFT128 ScreenKey is an intelligent device with an onboard microcontroller and graphical display controller. A fully implemented 4-wire SPI interface, with an expanded command set, allows designers to use simple ASCII control, full bitmap graphic display or a combination of the two. This smart switch supports downloadable display content and is designed to minimise bandwidth requirements from a host controller. This is particularly useful in a multi-ScreenKey environment.

Alan Cook, Managing Director of Foremost Electronics comments, “Our new TFT128 ScreenKey has major advantages over conventional push button switches. Instead of having to have an individual switch for every function of a system, the TFT128 ScreenKey can be continually reprogrammed to perform many functions in a control sequence and the display used to indicate the actual function at all times. This not only saves panel space and simplifies operation it can also improve ergonomics and aesthetics and offer cost savings. The display may also be used to prompt operators to take action during a process or in an emergency.”

The Foremost TFT128 ScreenKey offers two operating modes. High-level command mode simplifies integration into applications by using simple address codes such as, “text display”, “clear display”, “report key press” etc. High-speed mode implements a simple graphics only interface and delivers up to 10 frames per second frame refresh rate.

Overall dimensions of the TFT128 ScreenKey are 28.10 x 31.90 x 16.70mm and it is a simple click-fit into control panels with no need for soldering. A flex-tail cable terminated by a PCB connector is provided to connect to the host system. The TFT128 ScreenKey may be used in Portrait or Landscape mode depending on the application. The push button switch has two functions, a conventional push-to-make electrically isolated switch and an internal switch monitor which can report key activation to host systems for direct control or monitoring functions. Operating temperature of the TFT128 ScreenKey is -20 to +70°C and life cycle is up to 7 years from manufacture.