Processors and Microcontrollers Overview

Microprocessors and microcontrollers are similar but different types of electronic components. A microprocessor is a programmable device that serves the function of a central processing unit, or CPU. A microcontroller contains a processor core, but also contains other components that make it, essentially, an entire computer within the space of a single component.

 

Understanding the Differences

Understanding the differences between microcontrollers and microprocessors is most easily done by understanding their applications and specifications. Microprocessors are programmable devices utilized in a range of different industrial applications. They can provide control functions for circuit breakers, battery packs, provide the processing power behind the most sophisticated testing instruments and more.

The attributes of microprocessors also provide insight into their differences with microcontrollers. Microprocessors are generally chosen by speed, the common term for the clock frequency of the device. Other variables that may influence the choice include the data bus width, the instruction set architecture, the fabrication technology, the pin count and other variables. In particularly demanding applications, specifications such as the maximum and minimum operating temperatures may be vital to ensuring that the device functions as intended.

Microcontrollers are utilized in embedded systems. These are programmable devices that come in varying data bus widths, RAM sizes, with different types of device cores and with the capacity to handle different sizes of program memories. Instruction set architecture, frequency, supply voltage and other specifications are also vital to choosing the proper microcontroller for the job.

In industrial settings, microcontrollers are often employed in automation, allowing machinery, tools, instruments and other systems to be automatically controlled.

 

How They’re Made

Microprocessors and microcontrollers are both silicon components, which share a great deal in their manufacturing process.

Silicon components are derived from sand. Quartz sand is melted down into crystals, which provides a perfect lattice structure inside the material. In order to keep the materials pure, they are handled in clean rooms that are sometimes thousands of times cleaner than operating rooms.

These silicon crystals are cut into wafers and, to prepare them to receive the circuitry that will eventually allow them to serve as processors, they go through hundreds of different manufacturing steps along the way. These manufacturing steps are done in hermetically sealed equipment, preventing contamination.

When wafers have been fully prepared to be imprinted with their circuitry, they go through a process called photolithography. This involves using light to etch the circuits onto the wafers. The disc is coated with a photoresistive material. After the disc is coated, UV light is used to transfer the design of the circuit to the wafer. A developer is used to remove the parts of the disc that have been exposed to UV light, which creates a template for making more of the circuits.

The complexity of these devices is astounding and, in fact, they constitute among the most sophisticated manufactured products ever produced by humanity. Each of these completed wafers has billions of transistors etched onto its surface. These transistors serve as the switches that allow binary logic to be processed.

After the circuit is etched onto the wafer, the device is put through further steps in which its electrical properties are specified.

In some cases, a process called doping is used to change the characteristics of the silicon material. This involves deliberately introducing impurities into the silicon itself, another very precise and very demanding process.

Once the circuit is etched onto the wafer, conductive material has to be introduced to carry the electricity between the components. Copper or other materials may be used. This is then ground down so that there are no short-circuits on the device.

Despite the fact that this process is so precision oriented and the machinery used has to be hermetically sealed, the facilities used to manufacture chips are enormous. Some of them are larger than two football fields in length.

Once the device is manufactured, precise inspections using devices as sophisticated as electron microscopes are employed to ensure quality control.

This process can take more than a month to complete for every silicon wafer. When the devices are completed, they can be used in microprocessors or in the microprocessors that form components of microcontrollers.

 

New Innovations

Despite the enormous complexity and technological sophistication involved in the manufacture of microprocessors and microcontrollers, those manufacturing processes are always being advanced. Currently, one of the breakthrough processes involves manufacturing microprocessors that use light to transmit communications throughout the circuitry on the device rather than electricity.

This would result in microprocessors and microcontrollers that are enormously more efficient than current designs.

For decades, the number of transistors that can be fit onto the surface of a microchip has doubled at a regular rate. This has allowed increasingly powerful and sophisticated microprocessors to be manufactured. Where manufacturing technology reaches its limitations, some producers have started making multi core processors, which effectively increase processing power without greatly expanding the area that the circuitry takes up or the power consumption required to operate it.

 

Understanding the Differences

Because a microcontroller consists of what amounts to an entire computer on a single chip, it’s easy to make the mistake of thinking of them as inherently more sophisticated devices than microprocessors. This, however, is not necessarily the case.

Both of these types of components are very sophisticated. Their differences are illustrated in their potential.

The microcontroller component will come with a fixed amount of RAM, ROM and a CPU included on the component. This is why the devices are sometimes referred to as minicomputers. The term computer on a chip is used to refer to these devices, as well.

Microcontrollers can be programmed. This allows them to be used in applications where their input and output can be used to control devices. These are typically very purpose specific devices. For example, a microcontroller may be installed on the motor on a piece of industrial equipment, allowing its speed to be controlled automatically as needed based on the input and output the microcontroller receives and produces.

Where microcontrollers are concerned, they provide the ability to perform sophisticated functions at a very low price. While they are sophisticated devices, they are not particularly powerful. They have low amounts of RAM and ROM, limited I/O ports and generally operate at much lower frequencies than microprocessors. This has the inherent advantage of making them very cost effective solutions to complex industrial needs. Reprogramming or replacing a microcontroller is neither particularly difficult and is certainly not expensive.

A microprocessor is typically more expensive than a microcontroller and operates at a much higher frequency. The microprocessor component only consists of the CPU. It’s only function is to process digital information. Memory has to be provided separately.

Microprocessors are most commonly found in desktop computers and other types of sophisticated computing devices. These components are characterized by their enormous flexibility. A microprocessor can lend its processing power to any task demanded by program that the computer runs.

When differentiating between these two devices, it’s convenient to remember that a microcontroller will usually be used in a very specific role. It will have a simple program that allows it to take input, process it and deliver the desired output. It will not do anything beyond these simple functions.

Conversely, a microprocessor can be used for myriad different applications. Defining their applications is best done in broad terms. A microprocessor, for instance, might be used for purposes as expansive as programming or processing video.

 

Are they Interchangeable?

Generally speaking, microprocessors and microcontrollers are not interchangeable in the same applications. Aside from the obvious fact that a microcontroller is generally utilized because of the enormous convenience of having an entire computer on a chip, the cost differential is such that interchanging the devices is seldom practical.

A microcontroller quite simply will not have the processing power required for most of the applications for which microprocessors are used. On the other hand, a microprocessor will require more hardware to perform the same tasks that a microcontroller can perform on its own. A microprocessor generally will come at a much higher price than a microcontroller, as well, which could potentially drive the design and manufacturing expenses of very simple devices, such as automation control components, to excessively high prices.

 

Seeing them for their Advantages

Aside from applications, the advantages that the use of these devices offers provide good ways to differentiate the two.

With a microcontroller, the primary advantage is the fact that they cost so very little compared to the functionality that they provide. This not only means that the cost of producing controllers and other devices for industrial use is greatly reduced, it also means that the cost of developing them is reduced, as well.

Microcontrollers are inexpensive enough that they can be purchased in great quantities. This affords research and development departments a great number of components to work with and, if one should be destroyed, the financial loss is hardly extreme. The components can be programmed and reprogrammed over and over again, allowing different sets of instructions to be tested and the device to be used for different purposes.

Where a microprocessor is concerned, the expense of the device is offset by its flexibility. Most often, however, microprocessors are used in roles where a great deal of processing power is required and where their inherent flexibility is advantageous. An easy example to illustrate this incorporates both components.

Microcontrollers are typically programmed using a computer. The computer utilizes a microprocessor to provide the programming environment, provide debugging functionalities and other complex capabilities. The microcontroller itself might be programmed with a very simple program, but the capabilities of the microprocessor make it easy for the engineers to reprogram the microcontroller as needed. Once the microcontroller is programmed, it will generally be resigned to a very simple role where it’s inherent reliability, cost effectiveness and the adequate power they possess for handling simple tasks make them outstanding and consistent choices in industry.

 

Purchasing

Microprocessors are manufactured by very well-known names such as Intel, AMD and others. These companies have consistently made their processors more powerful and, at the same time, prices have become more affordable for even very sophisticated and fast processors.

Microcontrollers are manufactured by companies such as Analogue Devices, Cyprus Semiconductor, Energy Micro, Fujitsu and many others. They come in different families, including AT80, AT32UC3C and others. They also come with different options for course, data bus width and other variables. All of these have to be taken into account when selecting the devices.

Microcontrollers range in price from less than two dollars and up, making them very affordable components. Microprocessors typically start out at around the $50 range, with less powerful examples coming at a lower price tag but very high power processors costing considerably more.

Because of their very low cost, microcontrollers can generally be purchased and kept in stock for development needs and for replacing components that need to be changed out whenever required. Microprocessors, on the other hand, are typically purchased for specific builds and to replace components that have failed in computers.

When purchasing microprocessors, it’s important to make certain that the device has the proper mounting for the socket into which it will be installed, that it meets the voltage specification required and that it is able to handle the amount of processes required of it, determined by its speed.

Microcontrollers and microprocessors make automation possible and provide two similar, but different options for industrial uses. Microcontrollers are found in many different roles throughout most manufacturing facilities, utility plants and in most other large-scale and small-scale industrial locations. Microprocessors are incredibly common and, aside from being used in computers, are used in an increasing range of devices as they become smaller, more powerful and more affordable.

In addition to the devices becoming more powerful, they are also consistently becoming easier to work with. Excellent programming environments for microcontrollers and durable and very fast microprocessors have revolutionized many different industrial processes, office processes and beyond and advances continue to be made at a steady pace.