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CategoryⅠ IntroductionⅡ Development Background  2.1 Limitations of Microwave Oscillators  2.2 Origin of OEOⅢ Working Principle of OEO  3.1 The basic structure of OEO  3.2 Principle-based improvement directionⅣ Operating Characteristics of OEO  4.1 Advantage Performance  4.2 Disadvantage PerformanceⅤ Application of Optoelectronic Oscillator  5.1 Light Pulse Output  5.2 Clock ExtractionⅥ SummaryⅦ FAQ Ⅰ IntroductionThe optoelectronic oscillator (OEO) represents the first practical microwave oscillator that uses optical energy storage elements to generate signals with high spectral purity in the frequency range of several hundred MHz to more than 100 GHz. Many light wave energy storage components, such as fiber Fabry-Perot resonators, fiber ring resonators, optical micro disc resonators, etc. can be used to form OEO. It is a long fiber loop. The use of optical resonators can greatly reduce the size of OEO. Especially the optical microdisk resonator, which is a key component of integrating OEO in a single chip.  Figure1. Opto-Isolator OscillatorⅡ Development Background2.1 Limitations of Microwave OscillatorsGenerally speaking, the quality of the microwave signal generated by the microwave oscillator depends on the energy storage performance of the oscillation cavity. To produce high-quality microwave signals, a high-Q and low-loss energy storage unit is required. Current microwave oscillators are mostly based on electronics (such as dielectric oscillators) and acoustic (such as crystal oscillators) energy storage elements. When these components operate at frequencies above GHz, the energy storage characteristics will drop sharply, and the phase noise and spectral purity of the high-frequency microwaves produced will be poor. 2.2 Origin of OEOIn 1996, XSYao and L. Maleki of the California Institute of Technology Jet Power Laboratory developed a microwave oscillator based on a photonic energy storage unit during the use of photonics technology to improve the performance of a microwave system. This oscillator was named optoelectronic oscillator (OEO). Compared with microwave oscillators based on electronics and acoustic energy storage units, optoelectronic oscillators can generate high-purity microwave or millimeter-wave signals from several MHz to hundreds of GHz, and the Q value of their energy storage elements is as high as 1010, which generates high-frequency signals. The phase noise is as low as -163dBc / Hz at a frequency offset of 10kHz, and has both optical and electrical outputs. It is a very ideal high-performance microwave oscillator and is expected to be widely used in the future. Ⅲ Working Principle of OEO3.1 The basic structure of OEOThe basic structure of the optoelectronic oscillator is shown in Figure 2. It is a positive feedback loop composed of laser, electro-optic modulator, high Q optical energy storage unit (such as a certain length of optical fiber), photodetector, bandpass filter, microwave amplifier, phase shifter and microwave coupler. The energy of the oscillation comes from the injected light in front of the electro-optic modulator. After the injected light is modulated by the electro-optic modulator, it becomes an optical signal carrying a specific frequency. This optical signal is converted into an electrical signal by a photodetector, amplified, and then band-pass filtered. The filter filters out a specific frequency, part of which is used for output, and part of which is fed back into the microwave input port of electro-optic modulation to complete a cycle. After continuous cycling, a stable oscillation is finally formed. Since the optical oscillator uses a high-Q optical energy storage unit such as a low-loss long fiber, the output signal has extremely low phase noise. Figure2. Basic Structure of OEO3.2 Principle-based improvement directionIn addition, the loss in the optical energy storage unit such as optical fiber does not change with the change of microwave frequency, so theoretically the performance of the output signal of the optoelectronic oscillator will not deteriorate with increasing frequency. After nearly two decades of continuous exploration, the research on opto-electronic oscillators has made rapid progress. In the United States, opto-electronic oscillators have been successfully applied in cutting-edge technologies such as drones as high-quality local oscillators.  Nevertheless, in order to obtain a wider range of applications, optoelectronic oscillators need to be continuously improved in terms of performance and stability. Current research on optoelectronic oscillators is mainly focused on reducing phase noise, improving side mode suppression ratio, improving frequency stability, expanding output frequency, improving frequency tuning performance, miniaturization and multi-frequency oscillation, etc.Details are as follows:  (1) Phase NoiseThe phase noise of the output signal of the optoelectronic oscillator mainly comes from the thermal noise, scattered noise, and relative intensity noise of active devices such as lasers, photodetectors, and amplifiers. Phase noise can be reduced by optimizing the structure of microwave photonic links and the way the devices work. In experiments by D. Eliyahu and some others that produced extremely low phase noise (-163 dBc / Hz @ 6kHz) signals, a high power Nd: YAG laser with low relative intensity noise and an array amplifier with low phase noise were used. P.S.Devgan et al. Used low-biased Mach-Zehnder modulators and optical amplifiers to achieve an all-optical gain optoelectronic oscillator.  Compared with optoelectronic oscillators using electric amplifiers, the phase noise of this solution has been improved by 10dB. In addition, the use of high-power photodetectors can effectively reduce white noise, while the use of photodetector arrays to receive signals can effectively reduce the effects of flicker noise.Figure3. Phase Noise Modulation(2) Side Mode SuppressionIn order to obtain microwave output with low phase noise, the resonator of the photo-electric oscillator must have a very high Q value (Q = 2πfτ, f is the center frequency, and τ is the energy decay time), that is, a very large energy decay time is required. A larger τ can be obtained by increasing the fiber length, but as the fiber length increases, the longitudinal mode spacing (Δf = 1 / τ) in the cavity of the photo-electric oscillator decreases（As low as several tens of kHz）, in order to effectively suppress the non-oscillation mode and select a single oscillation frequency, a relatively narrow microwave band-pass filter is required. ①Dual-loop optoelectric oscillatorOne way to suppress side modes is to use a dual-loop optoelectronic oscillator. Two optical fiber loops of different lengths are formed in the cavity of the photo-electric oscillator. Only modes that satisfy the conditions for selecting the two loops at the same time can start oscillation. By selecting appropriate loop lengths, single-mode vibration can be achieved. The dual-loop optoelectronic oscillator scheme can be divided into an optical-domain coupled dual-loop structure and an optical-domain coupled dual-loop structure.  This research group proposed a dual-loop optoelectronic oscillator based on polarization modulation and polarization division multiplexing. The polarization beam splitter not only realizes the conversion of polarization modulation to intensity modulation, but also realizes that the incident light wave is divided into two orthogonal polarization states to form a double loop. The side-mode rejection ratio of the 10GHz signal generated by this solution reached 78dB. Compared with the electric-domain coupled dual-loop scheme, the optical-domain coupled scheme requires only one photodetector. Optical domain coupling dual loop schemes can also be implemented using wavelength division multiplexing technology.Figure4. A Dual-loop Optoelectronic Oscillator②Coupled optoelectronic oscillatorAnother method to suppress side modes is to use a coupled optoelectronic oscillator (COEO). The coupled optoelectronic oscillator includes two parts: an actively mode-locked laser loop and an optical feedback loop. The active mode-locked fiber laser loop can effectively increase the Q value of the oscillator. Therefore, a shorter fiber length can be used to obtain low phase noise. This research group used a non-pumped erbium-doped fiber to achieve a 10.7GHz stable coupled photo-electric oscillator with a phase noise below -120dBc / Hz @ 10kHz. (3) Frequency StabilityThe factors that affect the frequency stability of the optoelectronic oscillator are mainly two aspects:  ①The high-Q components in the system (including long optical fibers and narrow-band electrical filters) are susceptible to changes in the environment, and the output frequency is changed to cause the output frequency. Instability, especially the change of equivalent cavity length caused by environmental factors such as temperature. ②Because the filters used in optoelectronic oscillators usually have a relatively large passband range, they are within the gain bandwidth of the loop. There will be many side molds. One of these side modes may obtain sufficient gain during the change of cavity length to replace the original starting frequency, resulting in unstable starting frequency. In addition, the bias point drift problem of common electro-optic modulators will also affect the stability of the output frequency, but isolating the optoelectronic oscillator from the environment or using a temperature control device can reduce the impact of environmental changes on the system. For example, in experiments of XSYao, the optoelectronic oscillator was placed in a foam-filled box to isolate the influence brought by vibration. The active phase-locked loop circuit control is used to lock the oscillation signal of the optoelectronic oscillator to an external reference source, which can also effectively improve the frequency stability of the optoelectronic oscillator.Figure5. Frequency Stability(4) Working FrequencyTheoretically, the optoelectronic oscillator can generate signals from several MHz to hundreds of GHz, and the phase noise has nothing to do with frequency, but the high-frequency millimeter wave optoelectronic oscillator is difficult to realize. This is mainly due to the use of microwave devices such as photoelectric modulators, microwave couplers, microwave phase shifters, microwave amplifiers, and microwave transmission lines in optoelectronic oscillators, whose operating frequency is limited by electronic bottlenecks. Although there have been recent reports of high-frequency microwave or millimeter-wave devices, these devices are generally expensive, consume large power, and have poor performance. In response to the above problems, M. Shin et al. Used the LiNbO3 Mach-Zehnder modulator's half-wave voltage to the proportional relationship between the wavelength to achieve the simultaneous generation of 10GHz fundamental frequency and 20GHz octave signal. (5) TunabilityIn order to generate a broadband adjustable microwave signal, the optoelectronic oscillator needs to use a broadband adjustable high Q filter, which can be a tunable electrical filter, an optical filter, or a microwave photon filter. Limited by the electronic bottleneck, the tuning range of the output signal of the optoelectronic oscillator using a tunable electrical filter is limited. Optoelectronic oscillators based on microwave photonic filters usually have a large tuning range.Figure6. Schematic of The Tunable Opto-electronic Oscillator(6) Miniaturization ResearchOptoelectronic oscillators usually include laser sources, intensity modulators, long fiber delay lines, photodetectors, electrical amplifiers, electrical phase shifters, electrical bandpass filters, and other electrical or optical devices. These discrete electrical and optical components make the optoelectronic oscillator bulky and cause large power losses. By using high-Q optical resonators (such as whispering wall mode resonators) to replace fiber lengths of several kilometers, the size of the energy storage unit of a photo-electric oscillator can be significantly reduced. (7) Multi-frequency OscillationOptoelectronic oscillators usually only produce a pure single frequency signal. In applications such as wideband channelized receivers and multi-band radars, signals of multiple frequencies are required. In 2012, F. Kong et al. Used a birefringence characteristic of a phase-shifted Bragg grating to implement a dual-frequency optoelectronic oscillator. The disadvantage of this solution is that it can only generate signals of two frequencies, and the system is very sensitive to the environment. If a multi-frequency optoelectronic oscillator based on a single-phase modulator and a multi-wavelength light source are used, a single-passband tunable microwave photon filter can be formed on each optical carrier. By increasing the number of optical carriers, it will be easy to obtain more channels of different frequency signal output. Ⅳ Operating Characteristics of OEO4.1 Advantage PerformanceOptoelectronic oscillator is generally a positive feedback loop composed of light source, intensity modulator, filter and photodetector (PD). It takes advantage of the low loss characteristics of modulators and optical fibers to turn continuous light into stable, clean spectrum RF/microwave signals. The continuous light emitted by the laser is transmitted to the photodetector through the optical fiber after passing through the electro-optic modulator. The photodetector converts the light into an electrical signal and enters the frequency selection, amplification, and feedback modulation device.  During this process, the active device will generate noise disturbances of different frequencies. These disturbances are filtered by the filter at the output to the desired frequency and used to feedback and control the electro-optic modulator. The amplifier in the loop provides gain, and after several cycles of the signal, a stable oscillation can be established, and its oscillation frequency is mainly determined by the passband characteristics of the filter. 4.2 Disadvantage PerformanceAlthough the performance of the optoelectronic oscillator is outstanding, its system composition also determines some of its shortcomings. First of all, in order to obtain a high Q signal output, a long fiber is generally used in the cavity. At this time, the length of the cavity also determines the interval between the oscillation modes. The longer the cavity, the smaller the mode interval. In theory, a sufficiently narrow filter can be used to filter out unwanted modes, but it is quite difficult to obtain the device.  Secondly, in terms of the phase noise of the signal, the relative intensity noise of the light source, the photodetector and the electric amplifier will all affects the phase noise of the resulting microwave signal. Excessive bandwidth of filters and amplifiers will also reduce the signal-to-noise ratio in the passband range and affect the quality of the oscillation frequency.  Finally, because the loop is mainly composed of optical fibers, its cavity length is easily affected by environmental conditions and stress. The change causes the change of the fundamental frequency of the oscillation to cause the output frequency to drift or hop. In addition, the long optical fiber occupies a relatively large volume, which causes obstacles to the miniaturization and integration of the entire optoelectronic oscillator system. Solving the above problems is some of the key work for the final practical use of optoelectronic oscillators. Figure7. Cristal Oscillator Ⅴ Application of Optoelectronic OscillatorThe basic function of the optoelectronic oscillator is to generate high-quality optical and electrical microwave signals, but after being updated, it has also derived some new applications. In these applications, the electrical output of the photo-oscillator basically keeps the microwave signal output, but some changes occur in the light output part.5.1 Light Pulse OutputIn 1997 and 2000, X. Steve Yao and others successively analyzed and demonstrated the hybrid structure (COEO) of the optical resonator and optical oscillator loop provided by SOA to generate electric microwave signals and light pulses. This solution is similar to a regenerative mode-locked laser.  The main difference is that the photoelectric loop of COEO needs to be oscillated, and the final output mode is constrained by the selection of the two loops. In 2007, Ertan Salik demonstrated a COEO structure based on erbium-doped fiber amplifier (EDFA) to provide optical path gain, and obtained a 9.4 GHz microwave signal with ultra-low phase noise of -150 dBc / Hz (at a frequency offset of 10 to 100 kHz). Output and light pulse output with only 2 fs jitter. The optical pulse output mechanism of this structure is based on a fiber mode-locked laser. Therefore, in order to obtain high-performance output, there are high requirements on the design of the cavity length stabilization, dispersion control, and polarization maintenance of the optical cavity. Another feasible solution is to generate light pulses by changing the photoelectric modulation characteristics in the optoelectronic oscillator loop. In 2003, Jacob Lasri et al. Used electro-absorption modulator (EAM) to replace Mach-Zehnder intensity modulation (MZM) in the traditional scheme. By controlling the bias of EAM, a narrow modulation transmission window was obtained. Electric microwave signal and light pulse output. If a multi-wavelength light source is used in the light source part, this structure can also conveniently generate multi-wavelength light pulses. The structure of this scheme is relatively simple, but EAM generally has a large insertion loss, and the resulting pulse width is also wide.Figure8. Electro Absorption ModulatorIn addition, using a semiconductor laser operating under gain switching conditions or using a large-signal direct-modulation as the light source of the photo-electric oscillator, it is possible to obtain an electric microwave signal and an optical pulse output without requiring an additional modulator.5.2 Clock ExtractionBecause the structure of the optoelectronic oscillator has the function of frequency selection and amplification feedback, no matter whether the optical or electrical signal is injected into the optoelectronic oscillator, its clock signal (or frequency-divided clock) can be changed as long as it falls within the passband of the filter. The output can be recovered after locking and regeneration.  The maximum recoverable clock frequency is determined by the center frequency of the filter in the loop and the bandwidth of the modulator and the photodetector. X. Steve Yao et al.  Later, Caiyu Loun and others analyzed the extraction scheme of the frequency-divided clock based on the optoelectronic oscillator in 2002. By using the output electrical signal of the optoelectronic oscillator as a trigger signal to observe the injected optical signal on an oscilloscope, the electrical signal at this time can be determined. Whether the output is a divided clock of the injected signal, and experimentally verified the divided clock extraction under the condition of 10 Gb / s injected signal. In 2005, Hidemi Tsuchida and his partners demonstrated a frequency-divided clock extraction experiment with an injected signal rate of 40 Gb / s and 160 Gb / s. Figure9. Clock RecoveryIt should be noted that this method also provides a new idea for clock extraction of non-return-to-zero (NRZ) signals. In theory, there is no obvious clock component for NRZ signals to be extracted, but as long as the frequency selection of the optical oscillator filter is carefully adjusted. The clock signal of the injected NRZ code signal can be found and generated by the window. Li Huo et al. proposed the clock of the injected 10 Gb / s NRZ code signal, and obtained the converted zero (RZ) at the same time in the optical output part of the optoelectronic oscillator. The EAM-based optoelectronic oscillator can also complete the clock recovery of the RZ code signal. In the experiments demonstrated by Jaoob Lasri et al., In order to obtain the optical clock pulse signal at the same time, a DC light with a wavelength different from the wavelength of the injected signal light was added. Since the power change of the injected signal light will form a periodic switching window on the EAM and transfer the clock information to the simultaneously injected DC light, the wavelength of this DC light is selected by the optical filter to complete the Oscillation can generate an electrical clock signal and simultaneously obtain an optical clock pulse at that wavelength. It should be said that in addition to optical and electrical microwave sources, pulse sources and clock extraction systems, there are other applications, such as generating dual-frequency signals, inserting encoders to form multi-function signal generators, and so on. However, various applications are based on the feature that the photo-electric oscillator structure can automatically generate stable low-phase noise microwave signals. Therefore, as long as it focuses on various fields that require high-quality microwave signals, many new applications can be developed. Ⅵ SummaryIt can be seen that as a high-quality optical and electrical microwave signal generator, the optoelectronic oscillator has great advantages and wide application prospects. Various unique application methods also lay the foundation for the multifunctionalization of the optoelectronic oscillator.  However, it is undeniable that the current optoelectronic oscillator is still mainly in the laboratory research stage. There is still a period of time before it can be practically applied in the national economic construction and the development of national defense science and technology. Its main constraints focus on how to make the optoelectronic oscillator system into a compact, integrated, and compact frequency control system. The realization of these requirements depends on the development and manufacturing process of new photonic microwave devices and corresponding active devices.  Although there are no direct targets for optoelectronic oscillators, recent literature reports show some opportunities. For example, utc-pd (uni-traveling -Carrier Photodiode) in optoelectronic detection can receive high optical power and have high power electrical signal output, which can reduce or avoid the use of electric amplifiers in optoelectronic oscillators. The development of integrated semiconductor laser and modulator technology makes it possible to miniaturize the light source and feedback modulation of the photoelectric oscillator. The high Q value photonic filter with semiconductor structure is helpful to realize the system integration and tunability of optoelectronic oscillator. It is believed that with the gradual maturity of these technologies, the optotoelectric oscillator will be applied in practice and play its due contribution.  Ⅶ FAQ1. What do you mean by optoelectronic devices?Optoelectronic devices are electrical-to-optical or optical-to-electrical transducers or instruments that use such devices in their operation. ... Optoelectronics is based on the quantum mechanical effects of light on electronic materials, especially semiconductors, sometimes in the presence of electric fields. 2. What are optoelectronic devices give example?Examples of optoelectronic devices are: laser diodes, superluminescent diodes and light-emitting diodes (LEDs), converting electrical energy to light. photodetectors (e.g. photodiodes and phototransistors), converting optical signals into electrical currents. 3. What is the working principle of optoelectronic devices?Optoelectronic devices are primarily transducers i.e. they can convert one energy form to another. These devices produce light by expending electrical energy. They can also detect light and transform light signals into electrical signals for processing by a computer. 4. What are Optoelectronics used for?Optoelectronic devices refer to components used to detect or emit electromagnetic radiation, typically in the visible and near-infrared (NIR) regions of the electromagnetic spectrum. Each of these functions exploits the photoelectric effect of materials, also known as light-matter interaction. 5. Is LDR an optoelectronic device?There are two types of optoelectronic devices. These are Photoconductive devices and Photovoltaic devices. Photoconductive devices detect variations in light intensity to activate or inhibit electronic circuits. LDR, Photodiodes and Phototransistors fall in this category. 6. What are optoelectronic junction devices?Optoelectronic junction devices are p-n junction devices in which, carriers are generated by photons. Photodiodes, light-emitting diodes (LEDs) and solar cells are examples of optoelectronic devices. A photodiode is a device that is used to detect optical signals. 7. Which substance has optoelectronic property?Unlike the majority of electronic devices, which are silicon-based, optoelectronic devices are predominantly made using III–V semiconductor compounds such as GaAs, InP, GaN, and GaSb, and their alloys due to their direct bandgap. 8. Who discovered optoelectronics?Three Bell Laboratories scientists, William Shockley, John Bardeen, and Walter Brattain, demonstrated the first transistor-based on point-contact germanium (Ge) device. On the other hand, the semiconductor laser was discovered 15 years later in 1962. 9. Is solar cell an optoelectronic device?Solar Cell is another example of an Optoelectronic device based on the p-n junction, and the operating mechanism of a solar cell is essentially the same as that of Photodiode in that, a p-n junction is illuminated by light and the photogenerated carriers are separated by the built-in electric field across the p-n junction. 10. What are optoelectronic devices Name any two optoelectronic devices?Examples of optoelectronic devices include telecommunication laser, blue laser, optical fiber, LED traffic lights, photo diodes and solar cells. The majority of the optoelectronic devices (direct conversion between electrons and photons) are LEDs, laser diodes, photo diodes and solar cells. 

IntroductionMany embedded designs use single board computer based on micro-processor and micro-controller(SBC) and modular system (SoM). However, people with more embedded applications can't bear the delay caused by the response time associated with software. Only the custom hardware can achieve the higher performance that these applications required, and the quickest way to develop custom hardware is to use FPGA. This article will introduce the advantages of using SoM to develop embedded systems that require higher processing power from FPGA, and will also cover the various FPGA SoM, and also discuss how they work when embedded in design and development.What is an FPGA? Intro for BeginnersCatalogs CatalogsFPGA: The Role of Modular SystemNew SoM based on SoC with processor and FPGAFunctions of SoM and SBCConclusion FPGA: The Role of Modular SystemThe modular system (SoM) can help designers to develop special shape size embedded systems with custom interfaces without having to develop kernel processing systems from scratch. Designers can insert SoM which has pre-designed and tested into pre-designed or customized cards to create embedded designs with the same functions as fully customized designs, but take much less time to develop hardware.Using SoM has several advantages over developing hardware from scratch as follows:1) Saving cost( in the process of developing and debugging the circuit board based on SoC, the non-recurrent engineering cost will be very high.)2) Multiple choices(benefiting the insertion ability of SoM)3) Developing hardware and software at the same time4) Reducing design risks5) Small packagesThe market, once dominated by microprocessors and micro-controllers, is now replaced by SoM, with through holes and socket components losing their leading role. Pin compatibility allows designers to select from a range of compatible processors that have the correct clock speed and appropriate on-chip memory capacity. However, with the increase of the number of pins and the adoption of surface mount packaging technology, this design method has become obsolete. And SoM has emerged as the times require, its shape size and substrate surface have the same function as the previous series of pin compatible micro-controllers.If SoM is used as the computing platform of the project, the design engineer can concentrate his energy and resources to develop the final application without being lost in the details of designing computing platform. For example, at the clock speed of hundreds of megahertz (MHz), the layout of the SDRAM circuit board connected to the application processor becomes increasingly difficult due to differential wire delay, noise, crosstalk and many other challenges. However, SoM vendors have done a lot of design work before the start of the project, which can solve these problems and cut the time of product launch.To select the appropriate SoM series for embedded development projects, we must carefully analyze various factors, including the expected requirements of embedded resources, as well as the design extendibility, future adaptability and ease of use. This helps to select the appropriate shape and substrate size of SoM, providing alternative options to meet known challenges and unexpected future challenges. If the selected SoM family includes multiple product members and has compatible appearance dimensions and connector base surfaces, the selection of the designers can be expanded to make the product better able to withstand the test of the future. New SoM based on SoC with processor and FPGASoM usually uses SoC which includes multiple application processors, but a new embedded processor, SoC, integrating FPGA, applies to the SoM design either, like the Zynq®-7000 SoC, Xilinx’s fully programmable processor. Xilinx Zynq-7000 SoC integrates the software programmability of Arm Cortex-A9 application processors with the hardware programmability of FPGA. Arm microprocessor, built in Zynq SoC,  combines enhanced peripherals with SDRAM memory controllers (called Zynq SoC's "processing systems" or "PS"), and performs all the software-based tasks typically handled by embedded microprocessors or microcontrollers, while integrated FPGA (known as Zynq SoC's PL: Programmable Logic) provides hardware I / O response time and hardware acceleration for embedded tasks that require faster execution speed.Xilinx Zynq SoC offers a variety of processor configurations and speeds, with even more options for FPGA structures on a chip. Choosing the SoM family based on hybrid processor FPGA SoC can expand the selection range and improve the future adaptability of the product, like Xilinx Zynq-7000 series. One example of such a SoM series is the use of the TE0782 family from Trenz Electronic (Fig.1) and the SoM supporting test panel TEBT0782-01 which adopts the Xilinx Zynq-7000. Three Members of the SoC FamilyTE0782-02-035-2I based on Xilinx Zynq Z-7035 SoCTE0782-02-045-2I based on Xilinx Zynq Z-7045 SoCTE0782-02-100-2I based on Xilinx Zynq Z-7100 SoCAll three SoMs have the same connector substrate, including three Samtec LSHM nonpolar connectors and hundreds of I / O pins, in addition, there are power and grounding pins between the SoM and the board.Fig.1 Trenz Electronic TE0782 SoMFig.1: TE0782 SoM from Trenz Electronic uses one of three Xilinx Zynq Z-7000 SoC models, as well as providing 1GB SDRAM and other non-volatile memory.The best way to see the flexibility of SoM design is to look at the TE0703 carrier board of the TE0782 SoM family, and then go back to SoM through the I / O pins to see SoM's resources.Fig.2: Trenz TE0703 Board Divides Many I / O Pins from the Relevant 4 x 5 cm SoM Boards to the Rest of the Embedded System.Many of the important I / O functions separated from the SoM board are shown in the block diagram of TE0703 as follows:1 Gbit/s EthernetUSB and Micro-USBHundreds of I/O pins(it can be configured as a singular I / O pin, or as a low-voltage differential signal pair.)Fig.3 Physical Map of Trenz TE0703-05( Trenz TE0703 family) Functions of SoM and SBCProcessing speed, response time and I / O capability are significant characteristics of SoM. However, embedded systems often integrate SBC, such as Arduino Uno and Raspberry Pi, because these products also have wide-ranging technique support. So Trenz Electronic also offers related versions of Arduino and Raspberry Pi: TE0723-03M ArduZynq and TE0726-03M ZynqBerry based on Xilinx Zynq-7000 SoC. These SBC bridges many existing plug-in cards, such as the expansion boards of  Arduino and various Raspberry.The FPGA capacity of Zynq Z-7010 SoC integrated into TE0723-03M ArduZynq and TE0726-03M ZynqBerry SBC is significantly different from that of FPGA integrated into three Trenz Electronic SoMs (using Zynq Z-7035 Zynq Z-7045 and Zynq Z-7100 SoC ). Although all Zynq-7000 SoC apply dual-core Arm Cortex-A9 processor, their FPGA on components are different. Volume of the Xilinx Zynq SoC Programmable Logic Unit Block RAM (MB) DSP slices is Z-701028K2.180Z-7035275K17.6900Z-7045350K19.2900Z-7100444K26.52020, Xilinx Zynq-7000 SoC (Z-7035, Z-7045 and Z-7100) used in Trenz Electronics SoM provides more FPGA resources than that of Zynq Z-7010 used in Trenz Electronic ArduZynq and ZynqBerry SBC.Xilinx Zynq-7000 SoC (Z-7035, Z-7045 and Z-7100) used in Trenz Electronics SoM provides more FPGA resources than that of Zynq Z-7010 used in Trenz Electronic ArduZynq and ZynqBerry SBC. In addition, TE0723-03M ArduZynq and TE0726-03M ZynqBerry SBC provide only 512-MB on-board SDRAM, while TE0782 SoM provides 1GB.Trenz Electronic provides various boards for its SoM, including TE0703-05, TE0706-02, TE0701-06, and TEB0745-02, which provide a lot of standardized I / O functionality. A certain card may be suitable for a particular embedded application, but the embedded system design can also be split into a customized design board that can accept SoM series products to meet different processing requirements. This flexibility highlights the advantages of using the SoM family as the basis for embedded design. And consistent standardized connector substrate allows SoM to be easily interchangeable to accommodate changes in system specifications. ConclusionSoM can significantly cut the time requirement of prototype embedded systems and reduce project risk. As long as the SoM profile and connector substrate are supported,  more FPGA resources of SoM can be inserted to meet the growing demand. In addition, a variety of compatible SoM based on Xilinx Zynq-7000 SoC combine the processing power of dual-core Arm Cortex-A9 processor with FPGA resources, which is helpful to accelerate the development of embedded design. The embedded design method based on SoM can not only shorten the time required to develop the hardware part, but also allow the software development to start earlier in the project, thus reducing the design cost. FAQ1. What is a FPGA used for?Image result for FPGA and ProcessorFPGAs are mainly used to design application-specific integrated circuits (ASICs). First, you design the architecture of such a circuit. Then, you use an FPGA to build and check its prototype. Errors can be corrected. 2. Is an FPGA a processor?With an FPGA, there is no chip. The user programs the hardware circuit or circuits. The programming can be a single, simple logic gate (an AND or OR function), or it can involve one or more complex functions, including functions that, together, act as a comprehensive multi-core processor. 3. What is difference between FPGA and processor?CPUs offer the most versatility and so are the best suited to perform general purpose computing. FPGAs can be used to perform more specific and specialized tasks but are not ideal for general computing purposes. 4. How many times can you reprogram an FPGA?Altera guarantees you can reprogram windowed EPROM-based devices at least 25 times. Altera does not specify the number of times you can reprogram or reconfigure FPGA devices because these devices are SRAM-based. An SRAM-based device can be reconfigured as often as a design requires; there is no specific limit. 5. What is SoM FPGA?The CompactRIO System on Module (SOM) is a small, flexible, embedded computer for industrial applications that require high performance and reliability. It combines an ARM processor, the NI Linux Real-Time OS, a programmable Xilinx FPGA, and a high-density connector to interface with application-specific I/O. You May Also LikeDiscussion on the influencing factors of clock in FPGA designTo Solve the Problems of Cloud Skyrocket--Edge Processing