In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. The 8051 became widely popular after Intel allowed other MANUFACTURERS to make and market any flavors of the 8051. They please with the condition that they remain code-compatible with the 8051. This has led to many, versions of the 8051 with DIFFERENT speeds and amounts of on-chip ROM marketed by more than half a DOZEN manufacturers. It is important to note that although there are different flavors of the 8051 in terms of speed and amount of on-chip ROM, they are all compatible with the original 8051 as far as the instructions are concerned. This means that if you write your PROGRAM for one, it will RUN on any of them regardless of the manufacturer.

In 1981, Intel Corporation introduced an 8-bit microcontroller called the 8051. The 8051 became widely popular after Intel allowed other manufacturers to make and market any flavors of the 8051. They please with the condition that they remain code-compatible with the 8051. This has led to many, versions of the 8051 with different speeds and amounts of on-chip ROM marketed by more than half a dozen manufacturers. It is important to note that although there are different flavors of the 8051 in terms of speed and amount of on-chip ROM, they are all compatible with the original 8051 as far as the instructions are concerned. This means that if you write your program for one, it will run on any of them regardless of the manufacturer.