ARM microcontrollers are very successfully positioned microcontrollers in the market. Billions of them are used in all areas where control, data processing, in interfacing is needed. ARM microcontrollers have evolved into a high-level product that provides high processing power with the minimum clock frequency and power usage. Practically all major manufacturers are developing their line or ARM processors that share the same standard core functionality, and variations between MCUs starts with peripherals and other external features. ARM microcontrollers are cheap and robust which makes them attractive to use in almost all applications. They are successfully taking the place of smaller microcontrollers like ARM or PIC. Hobbyists also are taking them over.