Difference between Microprocessor and Microcontroller
There was a time when the size of a computer was the same as the size of a bus. Yes, those were the days when computers were invented and vacuum tubes were used to design processors.
But now with time and advancement in technologies, processors have been so revolutionized that from the size of a bus they come in the size of a small chip.
Brain working behind automated and smart devices that we see today is basically a small embedded chip with the microprocessors or the microcontroller.
Microprocessor vs Microcontroller: Key Differences
- Architecture: Microprocessors require external components, while microcontrollers integrate all necessary components on a single chip.
- Functionality: Microprocessors focus on executing complex tasks, while microcontrollers are designed for controlling and monitoring specific applications.
- Complexity: Microprocessors have a more advanced and complex architecture, while microcontrollers have a simplified architecture tailored to specific applications.
- Power Consumption: Microcontrollers operate on low power and have power-saving modes, while microprocessors consume more power.
- Cost: Microcontrollers are more cost-effective due to their integrated components, while microprocessors can be more expensive due to the need for additional hardware.
- Development and Programming: Microprocessors require extensive software development and programming using high-level languages, while microcontrollers are programmed using low-level languages or specialized IDEs for embedded systems.
What is a Microprocessor?
As discussed in the introduction, vacuum tubes and relays were huge and unreliable as well, so they were soon replaced by transistors. With the advent of transistors, the CPU was no longer slow and bulky.
It consisted of a large number of transistors embedded on a chip called integrated circuit (IC). These Integrated Circuits based processors gave birth to microcomputers - computers with CPU on a microchip(microprocessor), a memory system, a bus system and I/O ports.
A microprocessor is a programmable silicon chip that contains a central processing unit(CPU), that is, it has computing and decision making capabilities. In other words, it is an integrated circuit(IC) containing the arithmetic and logical unit (ALU), control unit (CU) and register arrays on a single chip required to interpret and execute instructions from a program.
When combined and connected with other integrated circuits that provide storage for data, programs, input and output, it becomes the heart of a small computer, or microcomputer.
Programmable: The microprocessor can perform different sets of operations on the data it receives depending on the sequence of instructions supplied in the given program.
Integrated Circuits: It refers to a miniaturized electronic circuit consisting of semiconductor devices(transistors), as well as passive components bonded to a substrate or circuit board.
Some popular microprocessors are: Intel 8085 (8-bit microprocessor) and Intel 8086 (16-bit microprocessor)
Features of Microprocessor
- Von-Neumann Architecture-stores data and code together.
- Offers built-in monitor/debugger program with interrupt capability.
- Supports a large instruction set, providing variations of the same operations based on different addressing modes.
- It offers both serial and parallel I/O as system buses are provided externally.
- Instruction cycle timer.
- External memory interfacing is facilitated that is, memory can be connected externally.
Application of Microprocessor
Microprocessors are mainly used in devices like:
- Personal computers (PCs).
- Simple calculators.
- Computer Games.
- Accounting system.
- Complex industrial controllers.
- Military applications.
- Defense systems.
- Computation systems.
What is a Microcontroller?
As we know, a microprocessor is not a complete system and requires other components and peripherals to be connected externally. When we bring a microprocessor together with the other needed peripherals on a single integrated circuit, it becomes a microcontroller.
A microcontroller can thus be defined as a complete microprocessor system where memory (RAM/ROM), clocks, system buses, I/O ports, etc, all the necessary components and peripherals(other devices) are integrated with the microprocessor on a single chip.
So we can say that,
Microprocessor = Arithmetic Logical Unit (ALU) + Control Unit (CU) + General Purpose Registers (GPRS)
Microcontroller = Microprocessor + Memory (RAM and ROM) + System Buses (Data Bus, Address Bus, Control Bus) + Clocks + Input/Output (I/O) ports
What makes microcontrollers more economical than microprocessors is the reduction in cost, size and connection complexities of the system. Most of the automated devices and products that we see around us often use microcontrollers based embedded systems.
The above diagram shows how a microprocessor unit(MPU) is connected internally with the system components and peripherals all in a single chip to form a microcontroller system.
Features of Microcontroller
- Harvard Architecture- stores data and code separately.
- Processor reset
- Program and Variable Memory (RAM) I/O pins
- Device clocking central processor
- Instruction cycle timers
Application of Microcontroller
Microcontrollers are preferred in embedded products and following are some of its applications:
- Home appliances: Washing machine, water purifiers, refrigerators, microwave ovens, etc.
- Gadgets and devices: Calculators, keyboard, printers, modems, mobile phones, etc.
- Automobile engines, flight control systems, traffic lights, control systems, etc.
- Military applications.
Difference Between Microprocessor and Microcontroller
| Microprocessor | Microcontroller |
|---|---|
| A microprocessor is a programmable silicon chip that contains a central processing unit(CPU), that is, it has computing and decision making capabilities. | A microcontroller is a complete microprocessor system where memory (RAM/ROM), clocks, system buses, I/O ports, etc, all the necessary components and peripherals are integrated with the microprocessor on a single chip. |
| Microprocessor contains Arithmetic and Logical Unit (ALU), general purpose registers, stack pointer, program counter, clock timing circuits and interrupt circuit | Microcontroller contains the circuitry of the microprocessor in addition it has in-built ROM, RAM, I/O devices, timers and counters. |
| Since memory and system buses are provided externally, access times for memory and I/O devices are more. | Less access time due to in-built peripherals and hence processing speed is faster. |
| Microprocessor based system is more flexible from a design point of view as one can adjust the size of RAM, ROM and other peripherals as per requirement. | Less flexible as memory and IO devices are all in-built and fixed. |
| It is based on Von-Neumann Architecture, i.e., it has a single memory map for data and code/program. | Microcontrollers take advantage of the Harvard architecture, i.e, storing data and code in separate memory maps to speed up processing. |
| System requires more hardware and connecting peripherals externally makes the circuit more complex. | Hardware is reduced due to the single chip microprocessor system where all the peripherals are in-built and internally connected. Less hardware, reduces circuit board size and increases reliability. |
| Microprocessor based systems are expensive. | Everything comes in-built so the cost of a microcontroller based system is low as compared to the microprocessors. |
| Large instructions set: It has many instructions to move data between memory and CPU. | Instructions are straightforward. It has only one or two instructions to move data between memory and CPU. |
| It is generally used in personal computers where you can buy and connect peripherals based on your requirements. | Due to compact design and cost-effectiveness, it is preferred in embedded systems like washing machines, water purifiers, etc. |
Conclusion
The key difference between a Microprocessor and a Microcontroller is that Microcontrollers are widely used in embedded systems which are dedicated to perform specific tasks, whereas microprocessor-based circuits are for complex system designs.
The comparison table vividly depicts that both microprocessors and microcontrollers come with some advantages and disadvantages. The choice mainly depends on the system architecture, the hardware requirements and the budget.