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  • Ten Daily Electronic Common Sense-Section 133

    What are the management functions provided by the Central Coordination Station (CCo)?

    1. The new site joins AV1. Coordination of N;
    2. New sites join AV1. Certification of N;
    3. Admission control of time division multiplexing;
    4. Arrangement of time division multiplexing and CSMA scheduling in each index period.

    What are the characteristics of the LTC2970?

    1. With 14-bit multi-channel differential input and △∑A/D converter, when using the on-chip low-drift reference, the maximum error in the entire operating temperature range is ±0.5%.
    2. Adopt 7-channel A/D converter multiplexer, which has 4 external differential inputs, l 12V input, 1 5V VDD input and 1 on-chip temperature sensor input.
    3. With two current output type 8-bit DAC voltage buffers, the voltage buffer output can be set to low leakage and high impedance state.
    4. Built-in closed-loop servo algorithm to adjust the point-of-load voltage of the DC/DC converter to the desired value. The range and resolution of the voltage servo loop can be adjusted with two external resistors.
    5. With a variety of configurable overvoltage and undervoltage fault monitoring methods.
    6. It has a two-wire serial bus interface compatible with I2C and SMBus, two GPl0 pins and an ALERT pin.
    7. It has an on-chip 5V linear voltage regulator, which allows the use of an external power supply of 8-l5V.

    What is the working principle of joint management?

    1. LLC start, stop delay and PGOUT signal (tDELl and toEL2).
    2. Remote control 0N/OFF. NCPl910 also adds a remote control 0N/OFF terminal.
    3. Vcc undervoltage lockout (UVLO). The device incorporates an undervoltage lockout of %c to prevent the circuit from operating when %c is too low.
    4. Bias controller. It is recommended to add a 1-100nF decoupling capacitor between the VCC terminal and GND to ensure its operation. The window between Vcc(on) and Vcc(of0 is very small. Because the NCP1910 is powered by an external power supply, use a low-voltage source to supply power to the NCP1910, that is, by Power supply for the standby part.
    5. Overheating shutdown. An internal overheating shutdown circuit can disable the gate drive output of the circuit, and then keep the power switch off when the junction temperature exceeds the TSD level. The output stage is turned off when the temperature drops below 110°C Enable, the thermal shutdown function can prevent faults caused by device failure.
    6. 5V reference. The VREF terminal provides a precise 5V reference voltage. The PG and Brown OUT of the LLC stage and the frequency foldback circuit of the PFC stage are powered by it .
    7. Latch protection and reset. As mentioned above, there are three failure modes to latch up the PFC and LLC.

    What is an RS-485 repeater?

    RS-485 repeaters need to be used in the following situations: more than 32 stations (including repeaters) are connected to the bus, or the maximum length allowed by the network segment is exceeded (related to the transmission rate). the
    The RS-485 repeater is used to connect two bus lines in the PROFIBUS network to increase the number of stations.
    The repeater is used for electrical isolation between signal recovery and bus segments, and the highest transmission rate is 12 Mbit/s. Up to 9 repeaters can be installed between two nodes. There is no need to configure the RS-485 repeater, but it should be considered when calculating the bus parameters.

    The main steps of program migration?

    1. Use the fully compiled Boa file to download the /sbin of the development board through the serial port rz command. Create a directory Boa under the development board/etc directory, put Boa. The conf configuration file is downloaded to the /etc/boa directory.
    2. The Boa server is set up above, and the cgi program will be compiled next.
    3. Completed the cross-compilation of the Qt program. Download the executable file test to the development board, modify the permissions, and execute the chmod a X test command.

    What functions should a hardware of a MOST node have in order to connect to the MOST network?

    1. Clock recovery;
    2. Node address identification and decoding;
    3. Coordinated control and data flow management between devices;
    4. Power management;
    5. Initialization function.

    What are the functions of the physical layer procedures?

    1. Provide data transmission between DTE and DCE interfaces.
    2. Provide control signals between devices.
    3. Provide a clock signal to synchronize the data stream and specify the bit rate.
    4. Provide mechanical connectors (ie pins, plugs and sockets, etc.).
    5. Provide electrical ground.

    What is the thermoelectric effect?

    The hot electron effect is also caused by the increase of electric field strength due to the reduction of device size.
    While the strong electric field saturates the average velocity of the carriers, it increases the instantaneous velocity and kinetic energy continuously. Electrons with much higher energies than in thermal equilibrium are called thermionic electrons. the
    The collision of hot electrons with the crystal lattice causes impact ionization, which produces electron-hole pairs. The electrons flow to the drain terminal, while some holes flow to the substrate. The current that forms the drain to the substrate is called the substrate current. If hot electrons are injected into the gate, gate current will be generated. Both of these currents are undesirable in analog circuit design. the
    The magnitude of the substrate current is not only related to process parameters, but also related to the voltage applied to the drain depletion region and the drain current.
    The effect of this current is equivalent to a resistance from the drain to the substrate. When V is large, the substrate current will have a non-negligible impact on the output resistance. In circuits with high output resistance, substrate current often becomes a limiting factor.
    The substrate current of the PMOS tube is smaller than that of the NMOS tube. Therefore, as the size of the device shrinks, the power supply voltage must also be reduced to avoid the generation of hot electrons. Considering the influence of the short channel effect, it is necessary to make necessary corrections to the model of the MOS device.
    In sub-micron T technology, for analog circuits, the gate length of MOS transistors is not designed with the minimum size in many cases.

    What are the car manufacturers’ general-purpose single-chip systems for general-purpose vehicles?

    Many GM power control modules are mounted under the dash, and some are located under a plastic panel on the right front fender.
    Before l986, the power control module was called l60 baud (Baud) microcontroller. The baud rate refers to the speed at which the microcontroller processes input signals and executes output actions.
    Beginning with the 1986 model year, General Motors used the P4 microcontroller with a baud rate of 8 192 bps. 160 Baud microcontroller can be every l. It takes 25 s to update the sensor information once, but it only takes 0.2 s for the 8 192 Baud microcontroller to complete this function. Compared with the 160 Baud single-chip microcomputer, the P4 single-chip microcomputer has a larger storage capacity, which enables the P4 single-chip microcomputer to process 600,000 digital signals per second.
    In some 1995 General Motors vehicles, the vehicle control module (VCM) replaced the power control module. The vehicle control module performs the functions of the original power control module and anti-lock braking system (AB) module. In some cars, such as S/T trucks, the vehicle control module is installed in the engine compartment.
    GM’s Power Control Module consists of one or more removable chips that sit under the microcontroller’s access panel. Some l60 Baud power control modules have two removable chips, a programmable read-only memory and a calibration software package (CALPAK). The programmable read-only memory contains some special information required by the specific car that uses the microcontroller, such as Ignition advance program and the like.
    An alternate fuel supply program is included in the calibration package chip. If the chip controlling the fuel delivery fails, a backup fuel delivery routine in the calibration software package takes over. In this case, the fuel delivery may be imprecise, but the car can still be driven.
    In the P4 single-chip microcomputer, the programmable read-only memory and the calibration software package chip are combined into a memory-calibration (MEMCAL) chip. These plug-in chips are commercially available and can be replaced separately from the microcontroller.
    Because the vehicle control module has a non-removable electrically erasable programmable read-only memory, there is no removable programmable read-only memory, calibration software package, or storage-calibration chip. There is also a knock sensor module in the vehicle control module. Some GM cars are currently equipped with a new generation of expanded P6 microcontrollers.

    Altera Cyclone FPGAs have the following performance characteristics?

    • New programmable architecture for low-cost design.
    • Embedded memory resources support a variety of memory applications and digital signal processing (DSP) implementation.
    • Dedicated external memory interface circuit, supporting connection with DDR FCRAM and SDRAM devices and SDR SDRAM memory.
    • Support serial bus and network interface and multiple communication protocols.
    • On-chip and off-chip system timing management using embedded PLL.
    • Support single-ended I/O standard and differential I/O technology, LVDS signal data rate up to 640Mbps.
    • Processing power consumption supports Nios ll series embedded processors.
    • Low-cost configuration scheme using new serial configuration devices.
    • Quartus ll software 0penCore evaluation feature supports free IP functional evaluation.
    • Free support for Quartus ll Web Edition software.


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