Intel 8051. 30 years in devices, appliances and ... soft toys / Intel Blog

What do a vending machine, a traffic light and a talking teddy bear have in common? The question is probably not one of the simplest ones, so we won’t torment you: they are all controlled using the Intel 8051 microcontroller - perhaps the most popular controller for embedded systems in their entire history. And although back in 1996, 8051 was replaced by Intel with a more advanced model, its clones to this day continue to be produced by a dozen companies. It seems that such an unusual long-liver is worthy of at least a small post.


I would like to make a reservation right away. It’s more correct to talk about the mega successful family of Intel MCS-51 controllers, consisting of 13 representatives: 8031, 8051, 80C31.80C51, 8032, 8052, 80C32, 80C52, 8751, 8752, 87C51, 80C152, 8XC51FA. However, the 8051 still stands apart in it - it was this model that became a breakthrough, so in the future we will consider the whole series as a whole, and 8051 as an example.
Intel 8051 replaced its predecessor 8048 in 1980. The reason for his success was the combination of healthy conservatism and technological innovations, so necessary at that time and almost immediately picked up by the market. All these innovations in one way or another related to performance. The basic structure of an 8-bit arithmetic logic device has been preserved, but a huge number of bit-oriented operations have been introduced; the number of transfer commands without the participation of the battery increased; multiplication, division, and new subtraction commands were added. There are improvements when working with the stack.


Intel 8051 Controller

Changes in the structure of the time cycle of the microcontroller led to a significant acceleration of work with the external memory of programs and data. The address space of the internal program memory was expanded and the space of the external program and data memory was increased to 64 Kbytes. 16-bit registers of the command counter and data pointer allowed direct access to the entire range of addresses, which made it possible to implement fast processing of large data arrays. All software-accessible nodes of the microcontroller are reduced to a special area of ​​data memory, which made it possible to access them as ordinary cells of resident RAM. While maintaining the consumption of crystals, the maximum clock frequency of the microcontrollers was significantly increased to 12-16 MHz.


Generalized block diagram of the Intel 8051 controller

The Intel 8051 controller consists of the following main components:

• 8-bit CPU (1-byte ALU and hardware implementation scheme of multiplication and division);
• ROM programs with a capacity of 4 KB;
• RAM data with a capacity of 128 bytes;
• 32 duplex programmable interface lines;
• two 16-bit timers for counting external events and clocking the communication port;
• asynchronous duplex serial input / output channel with a speed of up to 375 kbit / s.

Intel 8051 was the first embedded controller to learn how to receive and transmit data simultaneously, which also predetermined its success. Now the MCS-51 had enough power for use, for example, in cable TV set-top boxes (there they are responsible for synchronization, decoding of audio and OSD). Another important step forward was the transition to CMOS production technology, which opened up for MCS-51 the world of portable equipment, and not only devices and devices, but, as already mentioned, wonderful and extremely progressive children's toys at that time, like the Talking Wrinkles bear (80C31 controller, 1986).


Talking Wrinkles toy promotional video

In 1990, Intel celebrated a peculiar anniversary - 100 million MCS-51 controllers released. This was truly the heyday of the series, the controllers then came out with a breathtaking speed - 1 piece in 0.7 seconds! And each piece was used: in automotive on-board systems of leading manufacturers such as Ford, General Motors, Saab, Volkswagen and BMW; in flight recorders and thousands of other important and necessary devices. Not surprisingly, the next 100 million were produced in just a few years. Now, of course, the pace is not the same, but interest in the MCS-51 still does not fade. There is only one example. In 2012, a new textbook was released in RussianIntel 8051 and programming for it. Just from this tutorial, we kindly borrowed some of the information and the scheme for the post.