Intel MCS-51
![Intel P8051 microcontroller.](/Images/godic/202501/01/KL_Intel_P80510525.jpg")
![SAB-C515-LN by Infineon is based on the 8051](/Images/godic/202501/01/SAB-C515-LN0525.jpg")
![i8051 microarchitecture](/Images/godic/202501/01/Intel_8051_arch.svg0525.png")
![Intel 8031 processors](/Images/godic/202501/01/INTEL8031AH0525.png")
The Intel MCS-51 (commonly termed 8051) is an internally Harvard architecture, complex instruction set computing (CISC) instruction set, single chip microcontroller (µC) series developed by Intel in 1980 for use in embedded systems. Intel's original versions were popular in the 1980s and early 1990s and enhanced binary compatible derivatives remain popular today.