This part is a kind of semiconductor called 80C31X.

Function of this product has CMOS single-chip 8-bit microcontrollers.

Manufacturers : NXP

Image and pinout :

Some of the text within the PDF file :

Philips Semiconductors Product specification CMOS single-chip 8-bit microcontrollers 80C31/80C51/87C51 DESCRIPTION The Philips 80C31/80C51/87C51 is a high-performance microcontroller fabricated with Philips high-density CMOS technology. The CMOS 8XC51 is functionally compatible with the NMOS 8031/8051 microcontrollers. The Philips CMOS technology combines the high speed and density characteristics of HMOS with the low power attributes of CMOS. Philips epitaxial substrate minimizes latch-up sensitivity. The 8XC51 contains a 4k × 8 ROM (80C51) EPROM (87C51), a 128 × 8 RAM, 32 I/O lines, two 16-bit counter/timers, a five-source, two-priority level nested interrupt structure, a serial I/O port for either multi-processor communications, I/O expansion or full duplex UART, and on-chip oscil [ ... ]

80C31X PDF Datasheet Download