FPGA vs. DSP: What are the differences between them

What is a DSP

Digital signal processing, or DSP, is a term that should be quite self-explanatory. Headphones, cellphones, smart speakers, studio audio equipment, in-car entertainment systems, and many other items contain the technology. In fact, it serves as the basis for contemporary audio goods. Since CPUs are intended to serve multiple purposes, you are undoubtedly already aware of the concept of a processor. A DSP is a type of processor used to analyze digital signals, such as audio. They are made to carry out mathematical operations like addition and subtraction quickly and efficiently. DSP chips are available in a range of shapes, costs, and performance levels. scaling down to tiny low-power chips for voice recognition in smart speakers from multi-channel processors in automobiles and professional studio equipment. They’re used to speed up the execution of audio-related algorithms while consuming less power than a typical CPU.

Figure 1: DSP  

What is FPGA?

FPGA devices are designed with logic elements and memory that are configurable. A generic FPGA can be configured to operate and support diverse applications as needed. The designs of FPGAs are also modular, and the end-user can implement multiple hardware designs to ensure the FPGA fits into specific systems. The end-user or programmer can take advantage of hardware description languages such as Verilog HDL, VHDL, and SystemC to implement the hardware’s design. Additionally, FPGA devices come with embedded memory, ARM Cortex-M embedded processors, and DSP blocks, resulting in a standalone system designed for a particular purpose. For instance, the necessity for external memory devices to allow the operation of an FPGA device that can manage massive data sets is removed. Designers have the choice of implementing the FPGA's system components in the embedded processor or creating hardware components by utilizing its general logic resources thanks to the flexibility of the FPGA's design.

Figure 2: FPGA  

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FPGA vs. DSP Features

DSP Features

• The upgraded Harvard structure and the Harvard structure with separated data and programs are used to execute instructions more quickly.
• Reducing the time it takes for each instruction to be executed by using pipeline technology.
• A multi-bus on-chip that can handle simultaneous data access and fetching of instructions.
• Multiplication and accumulation can both be performed in the same cycle using an independent accumulator and adder.
• It is practical for data transmission because it has a serial communication connector and a DMA channel controller.
• It is simple to create a small-scale system using an interrupt processor and timing controller.
• It has hardware and software that are ready to work together and can connect to different memories.

 

FPGA Features

• Configurable logic blocks
• Programmable interconnects
• Programmable routing
• Programmable I/O blocks
• On-chip memory
• Digital Signal Processing (DSP) blocks
• System-level interconnect
• Designing ASICs using FPGAs

 

The pros and cons of DSP

The advantages of DSP

• The flexibility of software.
• Appropriate for conditional procedures, particularly challenging multi-algorithm tasks.
• DSP leverages high-level programming languages like C or assembly for real-time program implementation.
• Utilizing DSP devices has the benefit of quick software updates, which significantly increase the system's dependability, adaptability, replaceability, and flexibility.

 

The disadvantages of DSP

• Restricted by the serial instruction stream.
• A DSP can only do extremely straightforward calculations on the data at sampling rates greater than a few MHZ.
• Long development cycle.

 

The pros and cons of FPGA

The advantages of FPGA

• The majority of the chip's logic gates and flip-flops, which total a lot, are look-up table structures.
• The implementation process is mostly SRAM.
• Large scale, high integration, quick processing, and efficient execution.
• Complex sequential logic designs can be completed using FPGA, and programming is versatile, practical, easy to do, and repeatable.
• Numerous FPGAs can be programmed indefinitely and repeatedly. Hardware overhead can be decreased by reconfiguration.

 

The disadvantages of FPGA

• After a power outage, the initial logic setup is typically lost.
• Timing is difficult to plan.
• Multiple events cannot be handled by it.
• It is not appropriate for operation under conditions.

 

FPGA vs. DSP: What are the main differences between them

	DSP	FPGA
Programming language	C is an assembly language used in DSP programming.	HDL, a mixed digital and analog description language that includes VHDL, Verilog, and Verilog-AMS, is mostly used by FPGAs.
Applicable occasions	DSP is appropriate for systems with low sampling rates, low data rates, multi-condition operation, processing sophisticated multi-arithmetic jobs, employing C programming, and using floating points. It is also appropriate for systems with multi-condition operation.	FPAG is appropriate for fixed or recurring processing jobs, fixed-point use, block diagram programming, high data rates, and systems with high-speed sampling rates (a few MHZ).
Characteristics	Rigid hardware and insufficient computer power. An increase in the system's DSP count is necessary to boost its performance capabilities.	It is a working system with expandable computing capacity thanks to flexible hardware, integrated memory, and embedded CPUs.
Cost	Application-specific DSPs are pricey compared to generic DSPs, which are quite inexpensive. DSP reconfiguration is likewise an expensive operation.	FPGAs can be modified to work with a variety of applications. They are simple to utilize due to their versatility.

   

FPGA board vs. DSP: Internal structure

The construction of hardware circuits with a specific purpose is the emphasis of FPGA. The internal resources are tiny components like Actel FPGA Versailles. The design description of the hardware circuit is first implemented on the FPGA's internal units using the HDL programming language. The signals inside and between the functional modules are connected by the wiring resources inside the FPGA to create a larger module. FPGA may internally implement digital circuits such as ALU, adder, multiplier, accumulator, FIFO, SRAM, DDR controller, FFT, HDLC, DMA, and PWM, therefore we must use it to construct a particular or general hardware function. One or more modules must use HDL to describe the design and implementation in detail. For the soft core of the FPGA, the contemporary FPGA may directly include microprocessors such as the ARM7, CoretexM1, Core8051, and others. Some FPGA producers include hardware modules directly inside the FPGA. Inside the FPGA, these are the hard cores. Pure digital circuits are implemented using conventional FPGAs. Only Actel's FPGAs in the market have adopted digital-analog hybrid PSC single-chip technology, which has significantly enhanced and broadened the range of applications and fields for FPGAs. Additionally, Slew can be adjusted, and most FPGAs contain phase-locked loops like PLL and DLL. Additionally, Actel has hardware components like OSC, RTC, and Power Manager. Even Actel's Fusion series also has built-in 600kbps 12bit Analog interfaces such as ADC and MOSFET Driver, internal resources such as UserFlashMemeory, FlashROM, etc. can realize real PSC, Bootloader, and other functions.

Figure 3: FPGA internal structure   DSP is mostly used for processing algorithms. Multipliers, adders, and other resources make up the majority of the internal resources. There are interfaces like SPI and UART that only take a specific set of commands. Internal resources are prepared and just need to be rearranged to meet client needs. Customers find it easy to use, but because it only does a few particular tasks, it is mostly employed in a few niche industries. In addition, DSPs incorporate a phase-locked loop, a counter, a baud-rate generator, and in certain cases, analog ADC interfaces.  

FPGA board vs. DSP: Functionality

For particular client product requirements, FPGAs are frequently utilized to implement digital circuit modules. In essence, they can implement all digital circuits, conventional digital functional modules, and digital processing modules. Although there are many various kinds of FPGA IO bridges and different types of FPGAs support different IO standards and protocols, the driving capabilities or voltages of these IOs are all programmable. Realization of any type of digital functional circuit, as well as bridge conversion protocol and high-speed, control-field, and signal processing. Additionally, Actel's Fusion can be utilized for power management, MOSFET driver, temperature detection, current/voltage detection, and its proprietary Flash process. The technology is battery-powered and can continue to function while the power is turned off. It also has extremely low power consumption, different operating modes (Static, Sleep mode), and a feature called the IGLOO chip that uses only 5uW when in Sleep mode. Such power usage can be used in mobile handheld devices like phones, GPS, and others to run more practical applications. Additionally, FPGA is utilized to realize the pre-design verification of ASIC. In addition, FPGA realizes DSP functions, CPU, MCU, memory controller, PWM, SVPWM, Clarke, Park forward and inverse conversion Realization, VGA control, data encoding and decoding, demultiplexing, signal processing up to Gbps, protocol conversion realization, etc., all of which are difficult for DSP to accomplish. Even if the DSP contains a large number of ready-to-use hardware modules, interfaces, and controllers, software programming is still necessary to implement PWM control, interface control, UART interface, SPI interface, and other functionalities. DSP, however, is unable to handle signals that are excessively high due to the instruction set's clock cycle restriction. Signals like LVDS are challenging to deal with when dealing with Gbps signals. The related application domains will therefore be constrained. Customers in various industries, however, have various design strategies and priorities. DSP is a popular tool among designers in several industries, including those that construct algorithms and process protocols. It won't be beneficial to move to FPGA for processing.  

DSP vs. ASIC vs. FPGA vs. SOC

DSP: The optimal execution of more complex digital signal processing algorithms (such as various transformation and quantization methods) requires a more specialized processor called a DSP. certain are distinct from general-purpose microprocessors in that they are SIMD-style (single instruction, multiple data) implemented, allowing instructions to be executed on multiple data samples to speed up certain algorithms.   ASIC: ASIC is a chip made specifically for a given application. It is typically created by a business for a particular purpose or just for one customer. Because it is tailored for a particular use, it can be created to meet the power and performance requirements of that application.   FPGA: To construct programmable hardware designs, an FPGA is a collection of programmable components with a programmable interface. Designs are often recorded in HDL files, which can subsequently be synthesized for FPGA technology, downloaded into an FPGA, and used in conjunction with other system components. Contrary to an ASIC, reconfiguration is easy by altering the design and uploading it to the same FPGA, making it particularly helpful for prototyping and making adjustments.   SOC: A SOC is a type of integrated semiconductor that can house a microprocessor, along with other system-level components, on a single chip.    

Conclusion of FPGA vs. DSP

A one-dimensional technique is used by conventional DSPs to process signals or analyze data. However, signal processing systems with flexible, extended, and decentralized capabilities are necessary in a digitalized environment where applications are numerous and interconnected within a system. FPGAs offer a reprogrammable solution that satisfies the needs of many DSP applications. Without in-depth technical knowledge of hardware description language, developers can build flow paired with hardware acceleration by using legacy codes to accomplish functions. Additionally, FPGA and SoC development boards give designers scalable capabilities for quickly prototyping embedded systems like DSPs. In comparison to the typical microprocessor, end-users have more design options when using a development board. For your applications, switching from conventional DSPs to the flexibility offered by host development boards is the best course of action.