PCB Blog - FPGA vs microcontroller

FPGA is an integrated chip mainly composed of digital circuits,belonging to a type of Programmable Logic Device (PLD);FPGA emerged as a semi-customized circuit in the field of specialized integrated circuits (ASICs), which not only solves the shortcomings of customized circuits but also overcomes the limitation of the number of programmable gate circuits in the original programmable device.It has the characteristics of flexibility and reconfigurability and is widely used in fields such as communication,digital signal processing,and embedded systems.It is a programmable logic device composed of programmable logic units and programmable interconnect resources.

A microcontroller is an integrated circuit chip that utilizes ultra-large-scale integrated circuit technology to integrate data processing capabilities such as the central processing unit (CPU), random access memory (RAM),read-only memory (ROM), various I/O ports,and interrupt systems A small and comprehensive microcomputer system composed of functions such as timers/counters (which may also include display drive circuits, pulse width modulation circuits,analog multiplexers,A/D converters, etc.) integrated onto a single silicon chip, widely used in the field of industrial control.

The difference between FPGA and microcontroller(microcontroller vs fpga)

1) Performance

When comparing the performance of FPGA and microcontrollers,it is necessary to consider the nature of the tasks they are designed to perform.FPGA excels in parallel processing tasks, while microcontrollers are optimized for sequential processing.

FPGA can perform multiple operations simultaneously.This parallelism enables FPGA to achieve high performance in applications that require concurrent processing,such as digital signal processing, image processing, and cryptography.For example,FPGA can process multiple data streams in parallel,enabling real time processing of high bandwidth signals or high-resolution images.

Microcontrollers are designed for sequential processing tasks.Their performance is determined by factors such as CPU clock speed, architecture, and instruction set.

2) Energy consumption

Power consumption is a key factor to consider when comparing FPGA and microcontrollers,as it affects the overall efficiency, battery life, and thermal management of the system.

FPGAs typically consume more power than microcontrollers.The power consumption of an FPGA depends on factors such as the number of active logic components,the switching frequency of interconnections,and I/O activity.In applications that require high performance parallel processing,the performance advantages provided by FPGA may increase its power consumption.

Microcontrollers typically consume less power than FPGAs.Their power consumption mainly depends on factors such as CPU clock speed,peripheral activity,and power management functions implemented in the device.Many microcontrollers include advanced power management features such as sleep mode and dynamic voltage regulation,which can further reduce power consumption during low activity periods.

3) Flexibility and Customization

FPGA has high flexibility and customizability due to its programmable architecture, allowing designers to create customized digital circuits based on their specific requirements. The logic blocks, interconnects, and I/O blocks within FPGA can be configured to implement various digital functions, from simple logic gates to complex digital signal processing algorithms.

4) Development time and complexity

FPGA development is more complex and time-consuming. The development process of FPGA typically involves writing code using Hardware Description Language (HDL), such as VHDL or Verilog.

There is a wide range of microcontrollers, each optimised for a specific purpose, which can help companies cut costs. For example, if you need an analogue-to-digital converter (ADC), two USB ports and at least 30 general-purpose input/output (GPIO) pins, you can choose a microcontroller that meets those needs perfectly. If only one USB interface is required, another microcontroller may be available that meets that specification. This versatility allows organisations to save money by choosing the lowest cost microcontroller without paying for unnecessary features.

In contrast, FPGAs are much more versatile. With a single FPGA, it is possible to configure five ADC interfaces without a USB interface, or three USB interfaces without an ADC interface.FPGAs are like a blank sheet of paper with numerous internal lines (i.e., routes) to support a wide range of different application requirements, but this also adds cost and complexity. In most cases, organisations do not have to pay for unused additional features and flexibility.

Volume is also a key factor in cost. The cost of buying 10 million microcontrollers is much lower than the cost of buying 100,000 FPGAs, a common phenomenon in consumer electronics.FPGAs are often produced and sold in smaller quantities, so their unit price is higher. This constitutes a cycle: if the number of FPGAs increases, the price may go down, but the increase in quantity requires that the price must go down. So, if the cost of FPGAs were comparable to that of microcontrollers, would more FPGAs be used? Possibly, but FPGAs are much more difficult to use, which is not conducive to the popularity of FPGAs.

Because microcontrollers are designed for a specific purpose, they are relatively easy to set up and can usually be configured and running in a matter of hours. FPGAs, on the other hand, require programming of all their internal components, which is very time-consuming. While there are some off-the-shelf hard IP modules available, most devices are programmable logic, i.e. they need to be designed in-house. Writing code in Verilog or VHDL is more time-consuming than in C, which is often the language of choice for writing microcontroller programs because it allows code to be written at a higher level, where one line of code can achieve more functionality. In contrast, low-level programming using Verilog and VHDL requires the manual creation of separate gate circuits and wiring, which adds complexity and cost. Engineers often tend to choose the simplest solution, and in most cases, microcontrollers are simpler than FPGAs.

In addition, device power consumption is a factor to consider. Many electronic devices rely on battery power, so it's critical to reduce device power consumption for longer use. The higher the power consumption, the more often the batteries have to be replaced, which is something users don't want. As microcontrollers are designed for specific uses, they can be optimised to achieve very low power consumption. For example, a single AAA battery can power a Bluetooth mouse for months. FPGAs, on the other hand, need to route between all the resources and their power consumption cannot match that of microcontrollers. This doesn't mean that FPGAs can't be used in battery-powered applications, but microcontrollers typically have the advantage when it comes to power consumption.

Microcontrollers typically have a simpler and faster development process because they can be programmed using advanced programming languages and development environments that software developers are more familiar with.Using high level languages,libraries,and frameworks can simplify the development process and reduce the time required to implement and test the required functionality.

FPGA is a highly versatile integrated circuit that allows users to create custom digital circuits by programming at the hardware level.They provide tremendous flexibility and are perfect for complex applications that require rapid prototyping and reconfigurability.On the other hand,microcontrollers are compact integrated circuits that combine the processor core,memory,and various peripheral devices into a single chip.They are designed specifically for specific tasks and provide cost effective solutions for simple to moderately complex applications.