Ten Daily Electronic Common Sense-Section 42

How many pins does the 28027 device have?

22 GPl0 pins, which can provide the bit trigger function of a single pin.

What are the basic classifications of programmable logic devices?

From the perspective of the development process of programmable logic devices, programmable logic devices from major companies emerge in an endless stream, but the naming of programmable logic devices is very irregular. Therefore, it is difficult for designers to make strict classifications according to the names of programmable logic devices.
There is no relatively uniform standard for the classification method in the application field of programmable logic devices. In general, designers often classify programmable logic devices according to their configuration and principles.
Classification by configuration: According to whether the information is lost after the chip is powered off, PLDs are divided into two categories: non-volatile PLDs and volatile PLDs. From the perspective of the internal structure of the device, PLD can be divided into two categories: array-type PLD and field programmable gate array FPGA according to the structure principle.

What is the role of the Transmit Buffer (TxB)?

The transmit buffer is the interface between the CPU and the BSP (Bit Stream Processor), capable of storing the complete information sent to the CAN network. The buffer is 13 bytes long, written by the CPU and read by the BSP.

What are the characteristics of the security subsystem?

• AES encryption and decryption accelerator, support ECB, CBC, CTR mode.
• Symmetric encryption algorithm DES/3DES accelerator, support ECB, CBC mode; secure hash algorithm SHA-1 hash engine.
• Random number transmitter, two 32-word send/receive buffers K are used for inputting and outputting data streams; DMA is connected to U for encrypting DMA1.

What are the routing algorithms for filtering injection nodes based on utility functions?

That is, if the encountered node has a higher utility value than the carrier, the message is passed to the encountered node. The utility function is further divided into purpose-related and purpose-independent.
The LSF (1st seen first spraying) algorithm is related to the purpose, and the algorithm is based on the last encounter time with the destination node as the judgment condition.
MMF (most mobile first) is the priority based on node ID, while MSF (most social first) algorithm is based on the encounter ratio of ID-identified nodes, both of which are routing algorithms independent of destination nodes.

Varistor specifications：

• For the selection of varistor, which indicators must be considered? For signal transmission lines, ESD protection must be considered:
  • The maximum working voltage of the varistor is greater than the working voltage of the circuit;
  • The capacitance of the varistor is different from that of the circuit. The signal transmission rate is matched, that is, the varistor does not attenuate the signal when the signal is transmitted;
  • The ESD resistance capability of the varistor is in line with the requirements of the whole machine.
• To protect the power supply line from induced overvoltage and operation overvoltage, it must be considered:
  1. The maximum working voltage of the varistor is greater than the circuit working voltage;
  2. The maximum peak current and energy tolerance of the varistor must be greater than the possible The induced overvoltage and operating overvoltage amplitude. Under the conditions of circuit structure, space location, and design cost, products with large capacitance or large size should be selected as much as possible. In fact, any type of chip zinc oxide varistor can perform induced overvoltage, operating overvoltage, and ESD protection.

What should I pay attention to when using CASE statements?

1. The value represented by the selected value or identifier in the WHEN condition must be within the value range of the expression.
2. The selection value in the CASE statement can only appear once, and no conditional statement with the same selection value can appear.
3. The execution of the CASE statement must be selected, and only one of the listed conditions can be selected.

Briefly describe weak signal processing techniques?

The weak signal processing technology mainly solves the problems of detection, noise reduction and separation of signals accompanied by noise.
In people’s daily life, noise interference can be seen everywhere, it often coexists with useful signals, and it is difficult to separate them by ordinary methods, thus seriously affecting the operation of the system and the normal monitoring of target signals. Therefore, in the field of signal processing, we always try to remove interference noise to obtain useful signals.
In some current scientific research and engineering practice, we often encounter the situation of strong noise, that is, the problem of detecting weak signals (nanovolt order) in the noise, which undoubtedly increases the difficulty of signal detection. For example, the measurement of fluorescent light intensity during material analysis, the detection of seismic waveform and wave speed, infrared detection, the measurement of bioelectrical signals, the reception of satellite signals, etc., these problems are attributed to the detection of weak signals in noise.
Therefore, weak signals mainly refer to small-amplitude signals submerged by strong noise. The purpose of weak signal detection is to extract useful signals from strong noise, or to improve the signal-to-noise ratio of the output signal of the detection system with some new technologies and methods.

What are the technical features of the KXL7135?

• KXL7135 has the following technical characteristics:
  1. No external components;
  2. It has output short circuit and open circuit protection circuit;
  3. The power supply voltage range is: 2.7~6V;
  4. With installation heat protection; 2kV HSMESD protection;
  5. Package form: SOTT89-3, To-252.

What is the combination of gasoline electromechanical control injection technology?

Combined with a three-way catalytic converter, diesel fuel injection system, automatic transmission (Automatic Transmission), intelligent variable valve timing and lift technology (i-VTEC), hybrid technology (HPS), and so on.
Many mechanical, electrical, and hydraulic technologies are closely combined to improve the performance indicators of automobiles, especially electronic control technology, which is rapidly improving with the rapid development of the microelectronics industry.