|Micro:bit IoT In C (I/O Press)|
|Wednesday, 17 August 2016|
The BBC micro:bit is capable of taking on a variety of roles including that of a powerful IoT device. In order to gain full access to its features and to external devices, however, you need to use C which delivers the speed crucial to programs that communicate with the outside world. Writing for the electronics enthusiast with a programming background, Harry Fairhead presents details of sensors and circuits with several complete programs.
Author: Harry Fairhead
Category: IoT; Electronics
A first “Hello Blinky” C program introduces the mbed online compiler, after that an offline approach using the yotta development environment plus NetBeans in used to discover how to control the micro:bit’s I/O lines and explore the basis of using the GPIO. For speed we need to work directly with the raw hardware and also master memory mapping and pulse width modulation. Sensors are connected using first the I2C bus, then by implementing a custom protocol for a one-wire bus, and eventually adding eight channels of 12-bit AtoD with the SPI bus, which involves overcoming some subtle difficulties and serial connections. The micro: bit lacks WiFi connectivity but using a low-cost device it can become an Internet server via its serial port. To conclude we look at the micro:bit’s LED display. This may only be 5x5, but it is very versatile, especially when you use pulse width modulation to vary the brightness level, something demonstrated in the classic game Commando Jump, written in C.
Harry Fairhead is the Editor of IoT-Programmer where you will find his other current and in preparation titles on Intel Edison, the Raspberry Pi.
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