89C51 is a low-voltage, high-speed 8-bit CMOS microprocessor with a 4Kbyte instant-read memory chip that is usually read-only memory as a microcontroller. It is a low-voltage, high-performance CMOS 8-bit single-chip microcomputer from the US company ATMEL. 89C2051 is a single microcomputer with an erasable 2 memory flash byte. The one-piece microcomputer has a read-only erasable that can be erased 100 times. The device is manufactured using high-resolution ATMEL memory technology and is compatible with MCS-51 sampling and emission pins. Combining the 8-bit multifunction CPU and flash memory in a singler, the ATMEL 89C51 is a very effective microcontroller and the 89C2051 is a very simple one. The 89C51 single-core microCuter offers flexible and cost effective solution for many embedded control systems.