More and more microcontroller boards are equipped with Arduino-compatible pinheaders (for example, see the ARM Cortex Board from Infineon http://www.ehitex.de/evaluation-boards/infineon/456/xmc1100-boot-kit-kit_xmc11_boot_001). In order to evaluate those controllers, a simple shield would be nice which fulfills the needs for beginners as well as for more advanced programmers.
For beginners, we could have the usual combination 2 LEDs, 2 Buttons and one potentiometer, extended by one foto-resistor. With this shield, one can develop, debug and test first programs using the digital output, digital input and analog input capabilities of the controller.
For advanced programmers, I would like to suggest one EEC/Gnublin and one ECC pinheader on the shield.
One can connect a lot of other boards by a ribbon cable to the EEC-pinheader, e.g. a 8x-Relay-Board, a Display-Board, a T-Sensor-Board, a Stepper-motor-driver and many more from the Gnublin Extension-board-series (see http://www.elektor.com/gnublin). The EEC has the following pinout:
To the ECC connector (see www.elektor-labs.com/ECC), one can connect the ready-to-be-published RS485- and 433-MHz-Wireless-Boards from Elektor, besides the possible Wifi- and Bluetooth-Boards for this connector. So the intermediate and advanced programmer can learn to make more sophisticated programs using the SPI, I2C, PWM and UART-features of the controller; but on the other hand the shield will be quite cheap because we only have a few components integrated.
The shield could also play an important role in a programming beginners course in Elektor (BASCOM and C).
5 V - 3,3 V compatibility:
Arduino-compatible boards may run on 5 or 3,3 V (at the IOREF-pin, this voltage can be detected). Besides of that, the EEC connector is specified for 3,3-V-IO and the ECC connector for 5-V-IO. Bi-directional voltage level translator like TXB0106 could be a solution (http://www.farnell.com/datasheets/1718799.pdf).
Elektor ref. 140009