ScreenKeys programmable LCD key switches use a very simple interface in which control data is transmitted synchronously into the key. A microcontroller interface to a single ScreenKey can be quickly constructed using only 4 lines, one for Data, one for Clock, 5v power and Ground.
A better alternative to the above design uses a hardware generated clock instead of software generated. A parallel-to-serial converter is used to clock data out to the ScreenKey. This design greatly simplifies the driving software and updates the ScreenKey LCD at a much faster rate. An application note and firmware source code for this example can be downloaded here.
The DemoComII microcontroller kit is a simple evaluation/development tool that uses the above hardware clock design with an Atmel 89C55WD microcontroller. The DemoComII microcontroller unit has two LCD keys onboard; one 32x16 ScreenKey and one 36x24 ScreenKey. The DemoComII board can be expanded by adding two additional ScreenKeys if required. The DemoComII microcontroller kit ships with a pre-programmed ScreenKey demonstration application. Firmware source code for this demo application can be downloaded here.
The OEM-5400 Windows Development Kit is the ideal starting point for Product and System Designers who want to fully integrate ScreenKey LCD key technology in to their own product designs. The OEM-5400 Windows Development Kit operates via standard RS-232 interface. The OEM-5400 Windows Development Kit includes one panel of 12 ScreenKeys (in a 3x4 matrix configuration) as well as Windows Software Suite CD-Rom, power/data cabling and power supply unit.
ActiveX tools provide the developer with the ability to control ScreenKeys from a very low-level all the way up to a high-level hierarchical menu system. A Windows-based Editor allow users to design a complete user-interface (including graphics, text, backlight colours, menus and interactivity) independent to the ActiveX control.
The ScreenKeys Editor software has a very useful utility allowing the user to create bitmap images using a simple pixel editor and export the bitmap to an external binary or C-file.