MCS® 51 Microcontroller Family User's Manual

The MCS® 51 Microcontroller Family User's Manual is an excellent tutorial for beginners and a valuable reference manual for experienced developers. It contains:

  • A general description of the Intel MCS-51 architecture
  • The complete MCS-51 core instruction set reference
  • Specifications of some popular 8051 derivatives

A must for all 8051 newbies!!!

It has been published by Intel Corporation as a hardcopy (order number 272383-002) and in Portable Document Format (PDF). It is still available from several archive and mirror sites:

Download from: (14.9 MB)    Intel P8051AH

The original Intel file name was 27238302.pdf.
The file size is exactly 15643018 bytes.
The correct MD5 checksum is 8381f5c1b08fee7f4be7a876ca1a2e51.
Note that some sites have renamed or compressed the file!
In cases of link rot, please send me a mail.

¹)  Intel has recently discontinued support for the MCS-51 family.
²)  These sites offer a scan of the hardcopy in PDF format.


Last revised:   W.W. Heinz,   May 31, 2022