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    Developing and arranging applications for Arduin0 is very simple and convenient. What are the steps to follow?

    • Write the program code in the IDE and verify the correctness of the program;
    • Connect the Arduino0 development board to the host through the USB cable;
    • Click the “Download” button to download the executable program to the development board;
    • Press the development board the reset button, the program starts to run.

    Brief description of the structure and hardware of PROFIBUS?

    PROFIBUS is one of the most commonly used field bus standards in the world. It is included in the international standard IEC 61158 of the fieldbus with its unique technical characteristics, strict certification specifications, open standards, and the support of many manufacturers.
    PROFIBUS became my country’s first field bus national standard in October 2006 (GB/T 20540-2006).  
    PROFIBUS is an open field bus that does not depend on the manufacturer, and all kinds of automation equipment can exchange information through the same interface.
    PROFIBUS can be used for distributed I/O devices, drives, PLCs and automation systems based on PC (personal computer).  
    PROFIBUS technology is the only field bus that can meet two types of communication applications (manufacturing and process industry applications).  
    PROFIBUS is called type 3 in IEC 61158, and the basic part of PROFIBUS is called PROFIBUS-V0. In the new version of IEC 61158 in 2002, the contents of PROFIBUS-V1, PROFIBUS-V2 and RS-485IS were added. Added PROFINET specification as type 10 of IEC 61158.

    What is the weak signal detection of stochastic resonance theory?

    The stochastic resonance theory was originally used to explain the alternating periods of glacial and warm climate periods in meteorology. In recent years, with the development of science, it has been found that the stochastic resonance technology has a good application prospect for weak signal detection.
    The traditional weak signal detection method, whether realized by hardware or software, is based on the second noise reduction. Use various measures to suppress noise as much as possible, and then extract the useful signal.
    The stochastic resonance method is different, it works through a nonlinear system. A mechanism that converts part of the energy of noise into signal energy is used to enhance the detection of weak feature signals. 
    For a long time, people thought that “noise” was a nuisance that disrupted the orderly behavior of a system. It reduces the performance of the system and is a major obstacle to the detection of weak feature signals. However, it has been found that in some nonlinear systems, the increase of noise not only does not further deteriorate the characteristic signal output in some specific frequency bands. On the contrary, the local signal-to-noise ratio of the output is improved to a certain extent, which enhances the appearance of the signal. This phenomenon is called “stochastic resonance”.
    The stochastic resonance phenomenon and some nonlinear phenomena extended on this basis have opened up a new way for the enhanced detection of weak characteristic signals, which is of great significance in theory and application.

    What are the three parts of active power management?

    Active power management is divided into three parts: dynamic voltage and frequency scaling (DVFS), adaptive voltage scaling (AVS) and dynamic power conversion (DPS).

    What are Altera’s programmable logic products?

    Altera’s programmable logic products can be divided into three categories: high-density FPGA, low-cost FPGA and CPLD, and each product category has its mainstream products in different periods.

    Briefly describe vector IRQ interrupts?

    Vector IRQs have medium priority and handle interrupts quickly. Once a vectored IRQ interrupt occurs, the ARM processor enters IRQ mode. The PC points to the IRQ exception entry 0x18, and the address of the vector IRQ service routine is copied from the vector address register (VICVectAddr0 to 15) of the corresponding channel to the vector address register (VICVectAddr) of the VIC. The PC jumps according to the address in VICVectAddr and executes the corresponding service program. The entire process is done automatically by the VIC hardware without the need for user software intervention.

    What are the advantages of thermocouple sensors?

    It has the advantages of wide temperature measurement range, stable performance, accurate and reliable and so on. It is widely used in the field of biomedicine.

    What are the main features of the LTP protocol?

    1. In the LTP protocol, the data block is divided into two parts: red part (red-part) and green part (green.part). The confirmation and retransmission mechanism must be used when the red part data is transmitted, so as to ensure the reliable transmission of the red part data. The transmission of Green Ministry data is tentative and therefore does not use this reliable mechanism. The transmission characteristics of the red part data and the green part data in LTP just correspond to the transport layer protocols TCP and UDP in the Internet. The red part can provide a reliable transmission function similar to TCP, and the green part can provide an unreliable transmission function similar to UDP.
    2. The data blocks in the LTP protocol are segmented. The last segment of the red part in the data block is the end of red.part (EORP). When the receiver receives this part of the data, it indicates that the transmission of the red part has ended. At this point, the receiver must send an acknowledgment message to the sender, indicating that the part of the data has been fully received. When the sender finishes sending this part of the data, a timer is started. If the sender does not receive the confirmation message from the receiver within the time limit, the red part data will be automatically retransmitted. This mechanism ensures the reliability of information transmission. The end of the entire data block is called EOB (end of block).
    3. LTP data flow can only be one-way, so the confirmation and retransmission of data are different from TCP. The acknowledgment and retransmission messages of LTP are not directly attached to the data segment, but are encapsulated in a separate data segment.
    4. Deferred transmission is an important concept in LTP. The LTP protocol itself provides the status of the current connection to confirm the feasibility of transmitting data. Therefore, LTP often generates packet messages, and the packets that cannot be transmitted immediately are buffered in the queue, waiting for a suitable transmission opportunity.
    5. LTP relies on the accurate calculation of the time when the message arrives at the destination node, which is to ensure that the message can be retransmitted at the correct time. The lower bound is stricter than the upper bound for the time for the packet to reach the destination node. Because the strict lower bound will make the calculation time as early as possible, the cost is that the data retransmission operation may be redundant. But once the Nether is too loose, the calculated time may be later than the actual arrival time. The cost is that the data retransmission will not be timely, and the delay of data transmission will be increased.
    6. When the sender receives the information that the red part data is lost or damaged, it will start the retransmission mechanism. When the red part of the data block accounts for a large proportion, it is better to use multiple record points similar to EORP, rather than just use EORP as the only record point. The transfer session of the data block can be cancelled by the sender or by the receiver.
    7. LTP solves security problems through two mechanisms, Authentication and Cookie. The authentication mechanism can ensure the authenticity and integrity of the data segment, and the cookie mechanism increases the difficulty of the LTP engine suffering from denial of service (DoS) attacks.

    In general, what is the role of the logical macro unit structure?

    • Generally speaking, the logic macrocell structure has the following functions:
      1. Provide the registers or flip-flops required by sequential circuits.
      2. Provide various forms of input/output methods.
      3. Provide internal signal feedback to control the output logic polarity.
      4. Distribute control signals, such as the clock and reset signal of the register, and the output enable signal of the three-state gate.

    What are the main characteristics of the signal processing optimal processing method?

    • The criteria for optimal processing may be different, for example, the optimal criteria may be to obtain the maximum signal-to-noise ratio, or to have the minimum decision loss, etc.
    • The method and result of signal processing are related to the form of interference and are also closely related to the form of the signal.


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