The Next Generation: MCS(R) 251 Architecture Using advanced modular design techniques, Intel launched the next generation of its 8-bit (8051) architecture: the MCS(R) 251 architecture. By modifying code using the MCS 251 architecture instructions, performance can be increased up to 15 times! Even with existing MCS(R) 51 microcontroller code, system performance can be boosted up to five times!
The MCS 251 architecture delivers higher performance and a host of other enhanced features including an increased memory mix and addressing, low power, low noise, efficient high-level language support, enhanced instruction set and integrated features and functions. All products in the family are based on the new MCS 251 core architecture.
Most importantly, the new architecture maintains full binary code and pin compatibility with existing MCS 51 microcontrollers. That means you can drop in the 8XC251SB microcontroller, as well as future products based on the MCS 251 architecture core, into existing products with little or no development effort and still get increased performance.