SCM is an integrated circuit chip, is the use of large scale integrated circuit technology to a data processing capability of CPU CPU random access memory RAM, read-only memory ROM, a variety of I / O port and interrupt system, timers / timer functions (which may also include display driver circuitry, pulse width modulation circuit, analog multiplexer, A / D converter circuit) integrated into a silicon constitute a small and complete computer systems. SCM is also known as micro-controller (