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  • Ten Daily Electronic Common Sense-Section 142

    What are the ways in which message mailboxes work?

    • One-to-one working method: This working method means that one task sends a message to the message mailbox, while the other task reads the message from the message mailbox. This way of working is the simplest and most commonly used.
    • Many-to-one working method: This working method means that multiple tasks send messages to the same message mailbox, and only one other task reads messages from this message mailbox.
    • One-to-many working method: This working method means that only one task sends a message to the message mailbox, while multiple tasks read messages from this message mailbox.

    What is the watchdog timer reset?

    When the PMl2 bit of the PMl register is “1” (reset when the watchdog timer underflows).
    If the watchdog timer underflows, the microcontroller initializes the pins, CPU and SFRs.
    Program execution then starts from the address pointed to by the reset vector. the
    During watchdog timer reset, some SFRs are not initialized.
    In addition, because the PM01″~PM00 bits of the PM0 register are not initialized, the processor mode does not change after reset.

    What are the antenna port power design principles?

    The power of the antenna port is a key factor to be considered in the design of the indoor distribution system. the
    Different standards and different scenarios have different requirements on the power of the antenna port. The indoor distribution system with multi-standard antenna feeder must match the power of the antenna port.
    The so-called power matching refers to the transmit power of the antenna port that can make the coverage of single antennas of different standards as consistent as possible. The power of the antenna port should not be too large or too small. the
    On the one hand, the power of the antenna port should not be too large. If it is too large, it will exceed the national “Electromagnetic Radiation Protection Regulations” (GB 8702-1988), and will cause damage to human health. At the same time, too much transmit power may block the antenna ports of other systems and cause interference to the entire room distribution system. As a result, there are many cases where there is a signal, but the call cannot be made or the call quality is poor. the
    On the other hand, the power of the antenna port should not be too small. If it is too small, the coverage of the antenna is limited, and it is necessary to ensure the quality of indoor coverage. The overall indoor environment requires greater antenna density, which means more antennas. In this way, the material cost and construction cost of the room division system will increase. Of course, in addition to the disadvantage of increasing costs, the multi-point coverage of low-power antennas. Evenly covering the indoor signal and improving the signal quality is still beneficial.

    What is the driving force behind the development of TN technology?

    3G construction and IP-based transformation stimulate the demand for packet-based transmission;
    Packetized transmission requirements for 3G network evolution to LTE;
    Full-service and triple play requirements for packet-based transmission.

    What are the characteristics of the OLED driver?

    1. OLED is a low-voltage driving device, and the driving voltage is 0V to 30V.
    2. The OLED pixel can be equivalent to a light emitting diode connected in parallel with a capacitor. The capacitance value is related to the pixel area, ranging from 20pF to 30pF.
    3. OLED is an active light emitting device. The luminous brightness is proportional to the injection current, so the OLED is driven by a constant current source.
    4. Passive OLED devices all adopt a common cathode structure. That is, the cathode of the OLED is connected to the row electrode.

    What is data storage?

    R0 is composed of l6 bits and is mainly used for transmission, arithmetic and logic operations.
    R1~R3 are the same as R0. In some cases, the upper 8 bits (ROH) and lower 8 bits (ROL) of I∞ can be used as 8-bit data registers respectively.
    RlH, RlL are the same as ROH, ROL. You can also combine l and R0 as a 32-bit data register (R2R0), and R3R1 is the same as R2R0.

    What are the recommended working conditions for BQ24700/1?

    1. The power supply voltage (Vcc) is 7-20V, and the operating voltage of the selector is 4.5-20V.
    2. The input voltage of ACN and ACP terminal (⑩ pin, ⑥ pin) is 7~20V.
    3. SRN, SRP terminal (⑤ pin, ⑩ pin) input voltage is 5 ~ 18V.
    4. —PW—M, tile line 6 Li, surface Li terminal (① pin, ③ pin, ② pin) output voltage is 0.3 ~ 20V.
    5. ①~⑤, ⑧~⑩, ⑩~⑩ and ⑩~⑩ pin input or output voltage is one o. 3~8V.
    6. The working environment temperature (TA) is -40~85℃.

    What are the common faults and solutions for fiber optic transceivers?

    1. Fault phenomenon: The indicator light of the transceiver is off. Solution: Measure the output terminal of the AC/DC power transformer with the DC voltage range of a multimeter to see if the voltage is normal, if there is no output voltage. Use the resistance file of the multimeter to measure whether the primary side of the transformer is open circuit. If it is open circuit, replace the power transformer.
    2. Fault phenomenon: POWER light is on, RX light and LINK light are off. Solution: This fault phenomenon indicates that there is a problem with one optical path. Take off the fiber optic head, put it in a dark place, observe whether the light from the opposite side is coming, if not, replace the transceiver on the opposite side. If there is red light, observe whether there is red light at the transmitting end of the fiber optic transceiver, and how strong or weak it is. If there is no light or very weak, replace the transceiver.
    3. Symptom: The RX and LINK lights at the UTP end are off. Solution: The symptom of this failure is that there is a problem with the output. Use a wire tester to measure the twisted pair to the switch. If normal, it may only be a problem with the fiber optic transceiver. Carefully observe the fiber optic transceiver, there is a twisted straight-through switch, use a small screwdriver to fiddle with the switch several times. The RX light and LINK light are on, and the output is normal. This failure is caused by dirt getting into the switch.
    4. Symptoms: The indicators are normal, but the network speed is slow. Solution: Use a laptop to connect to the UTP end of the fiber optic transceiver and enter Windows98. Click “Start” * “Run”, and enter the “PingXXX-T” command (XXX is the IP address of the home page). You can find a breakpoint and replace the fiber optic transceiver. At this time, execute the Ping command again. If a break is still found, the fiber optic transceiver at the other end needs to be replaced.

    What are the classifications of the labels?

    According to whether there is a battery on the tag, the tags can be divided into passive tags (Passive Tags), active tags (Active Tags) and semi-active (Semi-active Tags) tags.

    What are the ways to improve the performance of WOLED?

    1. Using triplet excitons
    2. Improve carrier injection efficiency
    3. Balanced carrier transport
    4. Improve light extraction efficiency
    5. Comprehensive consideration of multiple technologies


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