Microcontrollers and microprocessors are crucial components used in a wide range of electronic devices. Though often confused as the same thing, there are distinct differences between the two. This article will compare microcontrollers and microprocessors in detail across various aspects like architecture, applications, programming and more.
Definition and Basic Working
A microcontroller is a compact integrated circuit designed to govern a specific operation in an embedded system. It consists of a processor, memory and programmable input/output peripherals on a single chip. Thus, a microcontroller combines the essentials required to execute dedicated tasks into a standalone unit.
Microcontrollers are programmed using languages like C, C++ or assembly language. The program code and data are stored in non-volatile flash memory. When powered up, it fetches program instructions from internal memory and executes them to control the attached system components. This predefined behavior allows microcontrollers to function automatically without human interaction.
A microprocessor is a general-purpose central processing unit (CPU) fabricated as a single integrated chip. It is a versatile digital logic device capable of performing arithmetic, logical, control and input/output operations based on instructions provided. A microprocessor must be interfaced with additional memory, peripherals and support components to construct a functioning computer system.
Microprocessors require software like operating systems, drivers and application programs to function usefully. Program code and data are stored in external memory devices. The microprocessor reads instructions and data from these memory chips and performs computations or interface actions on them. It serves as the ‘brain’ of a computer by interpreting and executing commands dynamically.
A microcontroller integrates a CPU with peripherals and memory on one chip suited for embedded applications. A microprocessor contains just the compute engine and must be linked with other chips to interact with electronics.
Microcontrollers and microprocessors exhibit major architectural differences in their internal organization.
- Microcontroller architecture (Image credit: Adafruit)
The architecture of a typical microcontroller consists of:
- CPU – Microarchitecture implementation like 8-bit or 32-bit core optimized for control tasks.
- Memory – Flash memory for code storage. RAM for data storage. EPROM for boot instructions.
- I/O Ports – Parallel and serial communication ports like UART, SPI, I2C, USB. Number of I/O pins varies.
- Peripherals – Inbuilt peripherals such as timers, ADCs, PWM generators and more.
- Clock Circuit – On-chip oscillator/resonator generates system clock signals.
All these components are integrated together on a single silicon chip optimized for specific applications. The small footprint enables microcontrollers to be embedded inside systems.
- Microprocessor architecture (Image credit: ResearchGate)
The architecture of a typical microprocessor consists of:
- ALU – Arithmetic logic unit performs computational operations.
- Control Unit – Generates signals that orchestrate overall operation.
- Registers – Data registers to store operands and results.
- Cache – High speed memory holding frequently used instructions and data.
- Bus Interface – Front side bus to communicate with other system chips.
A microprocessor provides only the computational engine and must be supplemented with external components like:
- Memory – ROM/RAM chips connected via a bus interface.
- I/O Interfaces – Device controllers linked for peripheral connectivity.
- Bus – System bus as a communication backbone.
This modular architecture allows versatility in configuring complete computer systems. But also makes microprocessors unfit for standalone operation.
Microcontrollers and microprocessors can be compared across several features:
|8/16/32-bit RISC optimized for control tasks
|Complex instruction set like x86 optimized for high speed computation
|KB to MB of flash, RAM and ROM
|Small cache memory only
|Timers, ADC, PWM, UART, SPI etc.
|Minimal or none
|10s of configurable GPIO pins with peripheral interfaces
|Few dedicated bus interface pins
|Low, <1W typically
|Tens of watts
|Miniature IC package
|Large IC package
|$1 to $2 typically
|$100 and up
|Ease of programming
|Require simple development environment
|Compilers and assemblers needed
This comparison shows microcontrollers are more self-sufficient chips designed for cost-effective control tasks. Microprocessors emphasize computational speed and need external hardware.
Microcontrollers and microprocessors tend to be targeted towards distinct applications:
- Embedded systems
- Internet of Things
- Automotive systems
- Industrial automation
- Consumer appliances
- Medical devices
Microcontrollers excel in systems that require:
- Precise real-time control
- Low power consumption
- Compact form factor
- Low costs
- Real world interfacing
They are normally pre-programmed for defined activities.
- Personal computers
- Image processing
- Engineering workstations
Microprocessors shine for general computing roles that require:
- Numeric processing speed
- High throughput
- Complex program execution
- Regular tasks
- User interactivity
Their flexibility allows running diverse software.
Microcontrollers and microprocessors differ significantly in their programming environments:
Typical microcontroller programming setup (Image credit: Crudenstoss)
- Done using an IDE on a PC with a programmer/debugger hardware.
- Code is written in C or assembly language, compiled into binary machine code.
- Entire program code is downloaded into microcontroller memory using the programmer.
- No operating system needed – the program has full control of the chip hardware.
- Programming provides custom functionality tailored for the target application.
- Often requires embedded systems development skills.
Typical computer system programming model (Image credit: ResearchGate)
- Application software runs on top of complex operating systems like Windows, Linux etc.
- High-level languages like C, C++, Java are used along with system libraries.
- Source code is converted into binary executables and stored on hard disks/drives.
- OS loads and runs programs and handles hardware resources.
- Program functionality depends on software developer skills.
- Requires computer/software engineering skills.
So microcontroller programs control hardware directly while microprocessor programs run on intermediate OS layers.
Development Tools Comparison
Specialized tools are used to develop software for both types of chips:
Microcontroller Development Tools
- Cross compiler – Converts source code into machine code.
- IDE – Integrated development environment e.g. MPLAB, Arduino IDE.
- Debugger/Programmer – Hardware programmer used to load code and debug via JTAG, ISP.
- Starter Kits – Development boards with microcontroller, I/O interfaces to build prototypes.
- Simulator – Software to emulate the microcontroller on a PC for testing.
- In-circuit Emulator – Duplicates microcontroller on an external board with debugging.
Microprocessor Development Tools
- Text editor – For writing and editing source code files.
- Compiler – Converts high-level code into binary executable programs.
- Linker – Joins compiled code with libraries to generate complete programs.
- Debugger – Software tool to step through code and analyze logic at runtime.
- Profiler – Instruments programs to analyze CPU and memory usage.
- Make – Build automation tool to compile code into finished executables.
Microcontrollers and microprocessors are optimized differently for speed, efficiency and reliability:
|1 MHz to < 200 MHz typically
|>= 1 GHz range
|< 100 MIPS
|High – 10s to 100s of MIPS
|Ultra low power – μA to mA range
|High power – tens of Watts
|High MTBF of decades
|Medium MTBF of years
|Junction temperature < 125oC typically
|Junction temperature may exceed 85oC
|Often 8/16 bit data bus width
|Modern types are 32 or 64 bit
|Cost per unit
|Low – $1 to $2
|High – $100 and up
So microprocessors aim for maximum speed and compute power while microcontrollers emphasize efficiency, compactness and real world interfacing capabilities.
Microcontroller vs Microprocessor – Summary
|Complete electronic circuit integrated in a single chip
|Mainly just the CPU elements in a single chip
|Contains peripherals, memory in addition to CPU
|Must be connected to external chips for system
|Optimized for reliable control tasks
|Optimized for maximum computational speed
|General purpose programmable
|Embedded, operates without an OS
|Runs operating systems and application software
|Hardwired logic, programmed behavior
|Program functionality depends on software code
|Low power consumption
|High power needs
|Inexpensive, $1 to $2 range
|Expensive, $100 range
In summary, microcontrollers are self contained controllers programmed via firmware for real world embedded systems applications. Microprocessors are versatile general computing engines that run software on computer systems.
Microcontrollers and microprocessors serve complementary roles in the world of electronics. Microcontrollers excel at providing low cost, power efficient and compact control solutions. Microprocessors enable high performance computing and flexibility. Knowing the key differences allows developers to select the best option for their specific application requirements.
What are some examples of common microcontrollers and microprocessors?
- Popular microcontrollers: PIC, AVR, STM32, 8051, ESP32
- Common microprocessors: Intel x86, Intel Atom, AMD Ryzen, Nvidia Tegra, Qualcomm Snapdragon
How does a microcontroller differ from a microprocessor?
- Microcontrollers integrate CPU, memory, I/O peripherals into a single chip optimized for embedded control.
- Microprocessors contain just the CPU and must interface with other chips to construct a complete system.
Why are microcontrollers used in embedded systems?
Microcontrollers offer a compact, low cost, real time control solution with multiple interfaces suited for embedded applications. They provide processing capabilities in a miniaturized, customizable package.
What determines if a microcontroller or microprocessor is chosen?
Microcontrollers for simple, defined control tasks needing minimal resources. Microprocessors where maximum computational speed, throughput and complex software execution are required.
Can a microcontroller be used to make a computer?
While possible, microcontrollers lack the speed and memory to be suitable for general-purpose computing needs. They are designed for minimal hardware control roles rather than number crunching.