Difference Between Microprocessor and Microcontroller: Pin Count and Processing Power

January 17, 2020 Cadence PCB Solutions

Placing a microprocessor on a motherboard of a computer

 

I used to be ignorant about baking needs like butter and margarine. Both have almost similar color, and I thought one would substitute the others. And when I got margarine instead of butter for my mom who’s trying her latest baking recipe, I learned the difference the hard way.

 A few years later, I started designing my first PCB project. Thankfully, I’ve kept in mind about the difference between microprocessor and microcontroller, else I would have messed up badly in my first job. If you’re still confused between the two, read on and you’ll have a better idea.

What Are Microprocessors And Microcontrollers

Most non-PCB designers would be familiar with the term microprocessor. It is the semiconductor chips that drive a personal computer. Mention microprocessors and brands like Intel or AMD pop to the mind. A microprocessor is a single-chip central processing unit that primarily executes program instructions.

Meanwhile, the term microcontroller refers to a dedicated chip that contains a processor unit, memory modules, communication, and peripheral controls. Microcontrollers are commonly found in consumer electronics like washing machines, remote control, and also widely used in industrial applications.

Basic Difference Between Microprocessor and Microcontroller

Below you’ll find a list of distinctions between microprocessors and microcontrollers. 

Architecture

Except that both microprocessors and microcontrollers are semiconductors, they can’t be more different from each other. As mentioned, a microprocessor is a pure central processing unit. It doesn’t have any RAM or EEPROM in the IC. Instead, it uses a system bus to connect to external memories, peripheral controls, and communication interface. 

Conversely, microcontrollers are available in different models, where they feature different sizes of Flash, RAM, connectivities, special function peripherals, and I/O ports. A microcontroller that is meant for the automotive applications can have very different specifications than one for wireless communication. 

A microprocessor executes instructions from RAM that is connected to it via a system bus whereas the microcontroller generally uses its internal Flash for code execution. As such, microprocessors have the upper hand in code execution as the read cycle of RAM is generally faster.

Speed

In terms of processing speed, microprocessors have the upper hand against microcontrollers. Microprocessors operate in the region of hundreds of Mhz or Ghz while microcontrollers are commonly available in tens of Mhz. The obvious difference in speed makes microprocessors ideal for data-crunching applications.

Power

Microprocessors consume more power than microcontrollers. Microcontrollers often feature power-saving capability that enables it to operate in low power or sleep mode. These features are not available in microprocessors. Besides, operating at higher speeds results in higher power consumption for microprocessors. 

Complexity

As a microcontroller is packed with necessary memory and peripherals modules in a single IC, the circuit design to create a functional application is often less complex. Minimal components are needed to complete the circuit.

Microprocessors are bare central processing units and need to be connected with memory chips, communication modules, I/Os, and timers. A system bus, be it 16-bit, 32-bit or 64 bit, take up considerable space on the PCB. This results in a larger footprint on the layout.

Microprocessor vs Microcontroller: What’s The Right Choice For Your Design?

Both microprocessors and microcontrollers are meant to serve vastly different types of applications. Microprocessors, with its high processing power, are meant for applications like graphic control, motherboard, or intense-data processing systems. Microcontrollers are targeted at compact or specific solutions like music players, drones, or robotic applications.  

Regardless of your choice, both microprocessors and microcontrollers have their own design challenges. Microprocessors usually have large pin counts, with a large number of them forming the system bus. You’ll need to ensure the data and address bus are routed in equal length to prevent timing issues. 

 

Screen of electronic devices and IoT applications

Microprocessors are used in graphic processors.

 

If you’re using a microcontroller, you’ll be concerned about having mixed signals operating reliably on a compact PCB. This means ensuring signal integrity for analog channels while ensuring the digital signals are not coupling noises to adjacent components.

Of course, both microprocessors and microcontrollers demand the best PCB design practice as a whole. With the proper PCB design software, your task of designing with either option is much easier. Utilizing a strong layout tool like OrCAD will ensure your design gets placed and laid out as required, as well as offering finalization options for your production teams. 

If you’re looking to learn more about how Cadence has the solution for you, talk to us and our team of experts.

About the Author

Cadence PCB solutions is a complete front to back design tool to enable fast and efficient product creation. Cadence enables users accurately shorten design cycles to hand off to manufacturing through modern, IPC-2581 industry standard.

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