51 MCU is collectively on all compatible Intel 8031 ​ ​ microcontroller instruction. The series is Intel s single-chip ancestor 8031, and later with the development of Flash rom technology, 8031 has made considerable progress, becoming one of the most widely used 8-bit microcontroller, which represents the company s model is ATMEL AT89 series, it among widely used in industrial measurement and control systems. Many companies have launched 51 series of compatible models, will occupy a large market in the future for a long period of time. 51 is a single-chip microcontroller-based entry, or the most widely used one. Note that the 52 series of microcontrollers generally do not have self-programming capability.