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Are you in the middle of designing an Embedded system with a microcontroller unit (MCU)? Then, let me ask you this, which microcontroller should you choose? Confused! I totally get it.
Choosing the best microcontroller for your project can really be intimidating. Because there are various technical features to look for in a microcontroller, and also there are other factors like the cost and the advance notice that can hamstring your project.
At the inception of the project, there is always this great temptation to hop on and select a microcontroller even before the details of the system have been talked over. However, this is a faux pas.
In this blog, we will provide you with an in-depth run-through to help you select the best microcontroller.
What Is A Microcontroller?
A microcontroller is like a microcomputer that is available on a single intermixed circuit. Microcontrollers are designed particularly to achieve certain operations in an embedded system, and it comprises a processor, a memory, and input/output peripherals.
We can say that a microcontroller chip is like a small computer on a chipset. However, in contrast to a processor, it consolidates the memory, the CPU, input/output, and some other peripherals on a single chip. There are numerous microcontrollers available in the market. And all microcontrollers have their distinctive features and are available in contrasting package sizes based on the capacity of the RAM and ROM.
Each and every microcontroller will be different from the other. Nevertheless, the microcontroller is like the brain of any project, and the boom or collapse of your project will depend on it. Also, one microcontroller can not be used for every project as every application will have different demands. So, choosing the best microcontroller chip for your project can become a complicated decision.
So, let’s look at some essential features that one should look for while selecting a Microcontroller.
Factors To Look For While Choosing a Microcontroller
Below are given some important factors that one should look out for while choosing a microcontroller.
The first thing that one should do before choosing any microcontroller for a project on an embedded system is to acquire a deep knowledge of the application for which the microcontroller-based solution is required. Regarding this, a technical specification sheet is always developed as it will help in understanding the particular features that a microcontroller will be used for in a project.
Based on the application of the system in which the microcontroller chip is to be used is made apparent when a microcontroller chip with a single-precision unit is supported for the device that will be utilized to perform tasks involving many decimal numbers.
If you will be able to understand how a microcontroller will be utilized in your project then you can certainly make the right decision.
Herewith the term microcontroller architecture, we mean, how the microcontroller is designed internally. There are generally two major architectures that are utilized in the designing of microcontrollers:
- Von Neumann Architecture
- Harvard Architecture
First, let’s talk about the Von Neumann Architecture. The Von Neumann architecture makes use of the same process to transmit data and collect the set of instructions from the memory. Thus, data transfer and instruction collection can not be done at the same time and so they are generally scheduled.
In contrast to this, Harvard Architecture uses a separate route for data transmission and instruction collection.
Moreover, both of these architectures have their own good and bad.
To make this point more clear I have to use some technical terms, let’s get on to it.
The Harvard Architecture is RISC (Reduced Instruction Set) system and thus they can carry out better instructions with lower cycles in comparison to the CISC (Complex Instruction Set) system on which the Von Neumann Architecture is used.
One main benefit of the Harvard-based microcontrollers is the presence of distinct paths for data and instruction sets that allows the detachment of the memory retrieval and the operations of the ALU (Arithmetic and logic unit). This will minimize the total computational power needed by the microcontroller chip and it eventually leads to cost reduction, low power consumption and heat dispel making them ideal for the designing of the battery-operated devices.
The microcontrollers come in different bit sizes, they can be either 8bits, 16 bits, 32 bits, or 64bits. At present, 64 bits is the maximum bit size possessed by any microcontroller. For all non-technical readers, the bit size in a microcontroller means the size of a “word” utilized in the set of a microcontroller.
Thus, an 8-bit microcontroller denotes every instruction, address, or variable in 8-bit. One of the main indications of the bit size is the memory capacity of the microcontrollers. In addition to this, the larger the bit size, the larger will be the number of unique memory locations available on the microcontroller chip for use.
For example, the 8-bit microcontroller will have 255 unique memory locations while the 32-bit microcontroller will consist of 4,294,967,295 unique memory locations.
And it is very essential to choose a microcontroller with a bit size that meets the data to be processed.
Plus, it is also important to note that the majority of the applications these days are around 32-bits and 16-bit microcontrollers because of the technological improvements done on these chips.
Networking For Communication
Communication among the microcontrollers, sensors, and actuators that will be used for the project might need the use of a network between the microcontrollers to facilitate the communications.
For example- to connect an analog sensor to a microcontroller a microcontroller should have enough ADC. Also changing the speed of a DC motor might need a PWM interface on the microcontroller.
The operating voltage means the voltage level at which a system is built to operate. It is also seen as a voltage level to which certain features of the system are related. In hardware, the operating voltage at times decides the logic level at which the microcontroller will communicate to make up the entire system.
Currently, the 5V and 3.3V voltage levels are the most admired operating voltage for microcontrollers and your decision should be based on these voltage levels.
Number of Input/Output Pins
The number of general or special I/O pins present in a microcontroller is the most important factor that will surely influence your choice of microcontrollers.
If a microcontroller possesses all the features that we have mentioned but doesn’t have the required I/O ports then it cannot be used.
One more thing to keep in mind here is while determining the amount of Input/Output pins for a project is the future improvement that can be done to the device and how this modification will affect the number of Input/output ports.
There are various kinds of memory associated with the microcontroller that a designer will look out for when making a decision. Here, the most essential ones are RAM, ROM, and EEPROM. The requirements of these memories might be difficult to estimate until you use them.
The memory of the microcontroller holds the firmware for the microcontroller thus even when power is disconnected from the microcontroller, the memory will not be used. But, this is the case with the program memory. The data memory is utilized during the run time. And all variables and data generated because of processing among other activities during the run-time are stored in the data memory.
Thus, on the basis of the complexity of computation that occurs during run-time can be used to determine the total amount of memory needed for the microcontroller.
Here, the package size means the form factor of the microcontrollers. Generally, microcontrollers come in packages that vary from QFP, TSSOP, SOIC to SSOP, and the regular DIP package makes the arrangement on the breadboard easy. Therefore, it is crucial to plan way ahead of time about which package will be best.
This can be the most crucial factor for some when selecting a microcontroller especially when it is delivered in a battery-powered application like IoT devices. Make sure that the microcontroller you are using is satisfying the power requirements for your project.
Supports For Microcontrollers
The microcontroller you will choose to work with should have enough support like code samples, reference designs, and if possible a huge online community. If you are working with the microcontroller for the first time then you can face different challenges and using these resources can help you overcome them easily.
Plus, make sure that your microcontroller comes with a good evaluation kit so that you can quickly gain expertise and get familiar with the toolchain for development. It will save lots of your time and will quicken the development process of the device.
Choosing the best microcontroller for your project will continue to be an issue that a hardware designer will have to face and there are still a few factors that can influence your choice of microcontrollers. Moreover, the factors mentioned above are the most important ones.
What do We do At Extern Labs?
Our team of embedded designers and software developers always succeed in coming up with the best possible solution to make every project a success. Starting from the very first point of choosing the right microcontroller and other electronic components, we work with improved and advanced technologies that will complement the project. We offer our clients the most constructive and result-oriented embedded and IoT solutions. Feel free to contact us anytime.
I hope that this blog will help you choose the best microcontroller for your project.
Thank you, for reading till the end!