Engineers who develop microcontrollers generally come across FPGAs.
Some readers might ask: What can FPGAs do? Are they more powerful than microcontrollers?
To put it simply, FPGAs can achieve tasks that microcontrollers can perform in certain areas, and in some fields, FPGAs are far superior to microcontrollers.
Of course, FPGAs and microcontrollers each have their own characteristics, and there are some differences in their applications. This article mainly discusses the strengths of FPGAs.
FPGAs (Field-Programmable Gate Arrays) are programmable hardware devices that can define the structure and function of their internal logic circuits through programming, offering high flexibility and customizability.
Next, let’s discuss several common application areas of FPGAs:
1. Communication Systems
FPGAs can be said to be omnipotent in the field of communication, thanks to the characteristics of their internal structure, which allows for easy implementation of distributed algorithm structures, greatly benefiting high-speed digital signal processing in wireless communications.
FPGAs can handle various communication protocols such as Ethernet, USB, PCI Express, SATA, HDMI, etc., enabling efficient data transmission.
In wireless communication systems, many functional modules often require a large number of filtering operations, which typically need a lot of multiplication and accumulation operations. By implementing distributed arithmetic structures with FPGAs, these multiplication and accumulation operations can be effectively realized.
Especially, Xilinx FPGAs integrate many resources suitable for the communication field, including: baseband processing (channel cards), interface and connection functions, and RF (radio frequency cards).
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Baseband processing resources mainly include channel encoding/decoding (LDPC, Turbo, convolutional codes, and RS codes) and synchronization algorithms (e.g., WCDMA system cell search).
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Interface and connection resources include high-speed communication interfaces (PCI Express, Ethernet MAC, high-speed AD/DA interfaces) for wireless base stations and the implementation of corresponding backplane protocols (OBSAI, CPRI, EMIF, LinkPort).
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RF application resources mainly include modulation/demodulation, up/down conversion (single-channel, multi-channel DDC/DUC for WiMAX, WCDMA, TD-SCDMA, and CDMA2000 systems), peak clipping (PC-CFR), and predistortion. In summary, as long as you are good at FPGAs, you can absolutely excel in the communication field.
2. Digital Signal Processing
FPGAs are widely used in digital signal processing, including filtering, FFT (Fast Fourier Transform), and digital signal generation. Through hardware acceleration techniques, FPGAs can achieve high-speed digital signal processing, meeting the real-time requirements of fields such as communications, radar, and radio.
In the field of digital signal processing, FPGAs are also unmatched, primarily due to their high-speed parallel processing capabilities. The greatest advantage of FPGAs is their parallel processing mechanism, which allows for the implementation of digital signal processing functions using parallel architectures.
This parallel mechanism makes FPGAs particularly suitable for repetitive digital signal processing tasks, such as FIR digital filtering. For high-speed parallel digital signal processing tasks, FPGAs far outperform the serial execution architecture of general DSP processors. Additionally, the voltage and driving capabilities of their interfaces are programmable, unlike traditional DSPs that are controlled by instruction sets, which are limited by clock cycles and cannot handle high-speed signals. For signals at the Gbps rate like LVDS, it becomes challenging. Therefore, FPGAs are also widely used in the field of digital signal processing.
3. Video Image Processing
With the changing times, people’s pursuit of the stability, clarity, brightness, and color of images has become increasingly high, evolving from standard definition (SD) to high definition (HD), and now even to Blu-ray quality images.
Due to their high speed and low power consumption advantages, FPGAs are widely used in high-speed image acquisition, real-time image processing, intelligent monitoring, and medical image processing applications.
This has led to an increasing amount of data that processing chips need to handle in real-time, and the compression algorithms for images have also become more complex, making it difficult to rely solely on ASSP or DSP to handle such large data volumes.
At this point, the advantages of FPGAs become apparent, as they can process data more efficiently, making them increasingly popular in the image processing field after considering cost.
4. High-Speed Interface Design
Having seen the performance of FPGAs in communication and digital signal processing fields, you might have guessed that FPGAs also have a place in high-speed interface design. Their high-speed processing capabilities and the ability to handle hundreds or thousands of I/Os give them unique advantages in this area.
For instance, if I need to interact with a PC to send collected data for processing or to transmit processed results to the PC for display, the interfaces for communication between the PC and external systems are quite diverse, such as ISA, PCI, PCI Express, PS/2, USB, etc.
The traditional approach involves using corresponding interface chips for each interface, such as a PCI interface chip. When I need many interfaces, I would require multiple such interface chips, which undoubtedly complicates our hardware peripherals and increases size, making it inconvenient. However, if we use FPGAs, the advantages immediately emerge, as different interface logics can be implemented internally within the FPGA, eliminating the need for so many interface chips. Coupled with the use of DDR memory, this will make data handling for our interfaces much more manageable.
5. Artificial Intelligence
If you have been following the tech news, you must have been inundated with news about 5G communication and artificial intelligence. Indeed, the 21st century has unknowingly progressed to 2020, and in these 20 years, artificial intelligence has rapidly developed, and the smooth development of 5G has further propelled AI forward. It is foreseeable that the future will undoubtedly belong to artificial intelligence.
FPGAs have also been widely used in the front-end part of artificial intelligence systems, such as autonomous driving, which requires the collection of various traffic signals like driving routes, traffic lights, obstacles, and speeds, necessitating the use of multiple sensors. FPGA can be used to drive and fuse these sensors comprehensively.
Additionally, some intelligent robots require image acquisition and processing, or sound signal processing, which can also be accomplished using FPGAs. Therefore, FPGAs are adept at front-end information processing in artificial intelligence systems.
6. IC Design
The term IC might sound particularly profound, something beyond the reach of ordinary people, and IC design is a job that only a few can handle. It is undeniable that the threshold for IC design is relatively high, but we don’t need to mythologize it too much. Simply put, we can compare it to PCB design, where PCB involves assembling components on a printed circuit board to create a specific function circuit, while IC design involves assembling MOS transistors and PN junctions on a silicon substrate to create a specific function circuit—one is macro, and the other is micro.
If a PCB design fails, it can be redone without too much loss. However, if an IC design fails and needs to be redone, the losses can be devastating. As the saying goes, once the cannon fires, it can cost a fortune. In the IC field, once lithography starts, the costs can be astronomical. The cost of photoresist is exorbitant, and the cost of photomask is also not cheap, along with hundreds to thousands of processes, including human resources, material costs, machine wear, and maintenance, which can lead to significant losses. Therefore, IC design emphasizes a successful first version.
To ensure the success of the first version of an IC, thorough simulation testing and FPGA verification are required. Simulation verification involves running simulation software on servers, such as ModelSim/VCS software.
FPGA verification primarily involves porting the IC code to the FPGA, using FPGA synthesis tools for synthesis, layout, and routing to finally generate the bit file, which is then downloaded to the FPGA verification board for testing. For complex ICs, we can also break them down into several functional parts for separate verification, placing each functional module on a separate FPGA. The circuits generated by FPGAs are very close to real IC chips, greatly facilitating IC designers in validating their designs.
For example, high-speed data acquisition in the power industry, high-speed, large data analog signal acquisition and transmission in the medical industry, radar, satellite, and guidance systems in the military, network security, industrial control, etc., are all application areas for FPGAs.
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