I think, we must also congratulation Philips, because they developed and sells most of 8051 drivates.
Philps is a milestone to keep the 8051 popular until now.

Also I have seen, that many people learned and still learn the 8051 on the good old Siemens 517.


My first contact with the 8051 was, as I removed some from devective hard disk drives. Its also my oldest 8031, marked with 8431 production year/week. The company mark is "MHS", I don't kwow, what it mean.
It goes really hot under power, because still NMOS technology (need 200mA = 1W). Then I learned the 8051 with an excellent Valvo data book written in German.

The copyright mark looks mysterious, I have different 8051, which are marked:
Intel '80
Intel '81
Intel '82
So it seems, nobody knows, when it was invented.


Also I have an old AMD data book, with several 8051 derivates:

80C32T2: 8032 without T2

80C321: internal watchdog, software reset, dual DPTR

80C324: 80C321 with port expansion mode for up to 14 additional ports, fully instruction compatible to P0..3 including bit acccess (really nice feature !), connected to P1, should be implemented with a CPLD.

Since they are marked preliminary, I don't know, if they are selled at all. Even if I used never AMD-derivates, I looked very often on this data book to understand and get hints for programming my Philips and Atmels.


And in 1994 I switched to the Atmel AT89C51 Flash derivates, a really impressive fast eraseble and programmable and cheap device at this time. And in 1995 the AT89C2051 was also the smallest derivate.


I miss the good old times, where every micro controller has its own comprehensive printed data book (data sheet, instruction set, programming examples, tool chain) and the manufacturer was happy to give it out for free.


Peter