This part is a kind of semiconductor called 89S51.

Function of this product has 8-bit Microcontroller.

Manufacturers : ATMEL Corporation

Image and pinout :

Some of the text within the PDF file :

Features • Compatible with MCS®-51 Products • 4K Bytes of In-System Programmable (ISP) Flash Memory • • • • • • • • • • • • • • • • – Endurance: 1000 Write/Erase Cycles 4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz Three-level Program Memory Lock 128 x 8-bit Internal RAM 32 Programmable I/O Lines Two 16-bit Timer/Counters Six Interrupt Sources Full Duplex UART Serial Channel Low-power Idle and Power-down Modes Interrupt Recovery from Power-down Mode Watchdog Timer Dual Data Pointer Power-off Flag Fast Programming Time Flexible ISP Programming (Byte and Page Mode) Green (Pb/Halide-free) Packaging Option 8-bit Microcontroller with 4K Bytes In-System Programmable Flash AT89S51 1. Description The AT89S51 is a l [ ... ]

89S51 PDF Datasheet Download