This part is a kind of semiconductor called 8042AH.

Function of this product has Universal Peripheral Interface 8-Bit Slave Microcontroller.

Manufacturers : Intel

Image and pinout :

Some of the text within the PDF file :

UPI-41AH 42AH UNIVERSAL PERIPHERAL INTERFACE 8-BIT SLAVE MICROCONTROLLER Y Y UPI-41 6 MHz UPI-42 12 5 MHz Pin Software and Architecturally Compatible with all UPI-41 and UPI-42 Products 8-Bit CPU plus ROM OTP EPROM RAM I O Timer Counter and Clock in a Single Package 2048 x 8 ROM OTP 256 x 8 RAM on UPI-42 1024 x 8 ROM OTP 128 x 8 RAM on UPI-41 8-Bit Timer Counter 18 Programmable I O Pins One 8-Bit Status and Two Data Registers for Asynchronous Slave-toMaster Interface DMA Interrupt or Polled Operation Supported Y Fully Compatible with all Intel and Most Other Microprocessor Families Interchangeable ROM and OTP EPROM Versions Expandable I O Sync Mode Available Over 90 Instructions 70% Single Byte Available in EXPRESS Standard Temperature Range inteligent Programming Algorithm Fast OTP Pro [ ... ]

8042AH PDF Datasheet Download