8051 FAMILY MICROCONTROLLER PROCESSOR ARCHITECTURE BASIC INFORMATION

THE 8051 FAMILY MICROCONTROLLER PROCESSOR ARCHITECTURE

You might wonder why the 8051 family of processors was chosen for this purpose, as it is a relatively old processor. If you read current technical journal articles, you might get the impression that all the action is in 32-bit micros.

That is primarily due to the fact that the companies that sell the high-end devices are working very hard to put their newest technology in front of their\ customers, and they are the ones who write most of the trade articles.


It is important to note that the trade press is always emphasizing the high end 16-bit, 32-bit, and larger processors due to their dependence on the advertising revenue from chip vendors. Though you would never guess it from reading these publications, it is only recently that shipments of 8-bit microcontrollers have exceeded 4-bit units.

It will be quite some time before the 16-bit micros will approach the sales volume the 8-bit units have  reached, and the 8-bit units are still growing in volume. According to one of the leading industry publications, there are more 8051 derivative CPU chips being produced than any other 8-bit micro.

Once you have learned the concepts of the 8051, you will find that the next architecture you need to use will be much easier to learn.

The 8051 microcontroller has the following characteristic:

• Interfacing to the processor’s multiplexed address/data bus provides valuable design experience.
• Development tools, including assemblers, simulators and compilers are readily available as freeware shareware and demo versions.
• It is available at a low cost, allowing low cost versions of in-circuit emulators, peripheral components, and single board computers to be purchased by the student.
• The 8051 is the most popular microcontroller family, with many derivatives available, and multiple vendors manufacture it.
• The 8051 architecture is available in a wide range of cost, size, and performance. For example, one version is available in a 20-pin small outline surface mount package for less than a dollar in volume, and another one is about eight to ten times the speed of the original 8051.
• The 8051 CPU is also available as a building block for custom chip designs, and is the most popular CPU for “system on a chip” designs. It is also the only readily available, non-proprietary building block CPU architecture available for chip design.

Software tools for the 8051 family, such as assemblers, compilers and simulators are available at no cost on the internet. Hardware tools, such as the combination software development kit and in-circuit emulator, are available for under $100, and complete design documentation is available on the web to allow anyone to build their own.

In addition, the 8051 has the simplest timing specifications of a device which can address external memory, making it practical to go into the details of the design which are necessary to understand.

With less than two dozen timing specifications (compared to several times as many for most other equivalent processors), it is possible to cover the timing specifications in detail.

Once this process is understood, it is a straightforward jump to understanding and using the larger number of equivalent specifications characteristic of other devices.

EVOLUTION OF MICROPROCESSORS TUTORIALS

WHAT IS THE EVOLUTION OF MICROPROCESSORS?


The evolution of microprocessors has been known to follow Moore’s law, which suggests that the complexity of an integrated circuit, with respect to the minimum component cost, doubles every 24 months.

This rule has been generally followed, since the humble beginning of microprocessors as the drivers for calculators to the present-day scenario where every system, from the largest mainframes to the smallest handheld computers, uses a microprocessor at its core.


The first microprocessor was introduced in 1971 by the Intel Corporation. It was a four-bit microprocessor, Intel 4004. Other four-bit microprocessors developed were Intel 4040 by Intel, PPS-4 by Rockwell International, T3472 by Toshiba and so on.

The first eight-bit microprocessor, named Intel 8008, was also developed by Intel in the year 1972. All these microprocessors were made using PMOS technology. The first microprocessor using NMOS technology was Intel 8080, developed by Intel in the year 1973.

Intel 8080 was followed by Intel 8085 in the year 1975, which became very popular. Other popular eight-bit microprocessors were Zilog’s Z80 (1976) and Z800, Motorola’s MC6800 (1974) and MC6809 (1978), National Semiconductor’s NSC 800, RCA’s 1802 (1976) and so on.

The first multichip 16-bit microprocessor was National Semiconductor’s IMP-16, introduced in 1973. The first 16-bit single-chip microprocessor was Texas Instrument’s TMS 9900. Intel’s first 16-bit microprocessor was Intel 8086 introduced in the year 1978.

Other 16-bit microprocessors developed by Intel were Intel 80186 (1982), Intel 8088, Intel 80188 and Intel 80286 (1982). Other popular 16-bit microprocessors include Motorola’s 68000 (1979), 68010 and 68012, Zilog’s Z8000, Texas Instruments TMS 9900 series and so on.

32-bit microprocessors came into existence in the 1980s. The world’s first single-chip 32-bit microprocessor was introduced by AT&T Bell Labs in the year 1980. It was named BELLMAC- 32A. The first 32-bit processor introduced by Intel was iapx 432, introduced in 1981.

The more popular 32-bit microprocessor was Intel 80386, introduced by Intel in 1985. It was widely used for desktop computers. The 32-bit microprocessor family of Intel includes Intel 486, Pentium, Pentium Pro, Pentium II, Pentium III and Pentium IV.

AMD’s K5, K6 and K7, Motorola’s 68020 (1985), 68030 and 68040, National Semiconductor’s 32032 and 32332 and Zilog’s Z80000 are other popular 32-bit microprocessors. All these microprocessors are  based on CISC (Complex Instruction Set Computers) architecture.

The first commercial RISC (Reduced Instruction Set Computers) design was released by MIPS Technologies, the 32-bit R2000. Some of the popular RISC processors include Intel’s 80860 and 80960, Motorola’s 88100 and Motorola’s, IBM and Apple’s PowerPC series of microprocessors.

While 64-bit microprocessor designs have been in use in several markets since the early 1990s, the early 2000s have seen the introduction of 64-bit microchips targeted at the PC market. Some of the popular 64-bit microprocessors are AMD’s AMD64 (2003) and Intel’s x86-64 chips. Popular 64-bit RISC processors include SUN’s ULTRASPARC, PowerPC 620, Intel’s Itanium, MIPS R4000, R5000, R10000 and R12000 and so on.