Some technical points encountered in work projects

Work notes: hardware-related knowledge

The maximum size of the standard video signal is 700mV, and the basic voltage is between 0.7-1 V. The camera output is basically a BNC connection tip: use A multimeter to test the two wires connected to the two ends. If you know the standard voltage, you 'd better test the standard voltage. Aviation plug: it is an electromechanical component that connects the electrical line. Therefore, the electrical parameters of the aviation plug must be considered first when selecting the aviation plug.

Av: Short for audio cable and video cable in home audio. The avvideo interface consists of three channels: the audio interface (red and white lines, which form the left and right channels) and the video interface (yellow)

RFID (radio frequency identification) technology, also known as electronic tags and radio frequency identification (RFID), is a communication technology that can identify specific targets and read and write relevant data through radio signals, instead of identifying the mechanical or optical contact between the system and a specific target.

POE (power over Ethernet) refers to cabling in the existing Ethernet cat.5 (cat-5 refers to over 5 lines, is a network cable, generally household network cable) without any changes to the infrastructure, while transmitting data signals for some IP-based terminals (such as IP phones, wireless LAN Access Points AP, network cameras, etc, it can also provide DC power supply technology for such devices. Poe technology can ensure the security of existing Structured Cabling while ensuring the normal operation of existing networks, minimizing costs.

The main power supply parameters of the Poe standard power supply system are: 1. the voltage ranges from 44 to 44 ~ The typical value is 48 V. 2. the maximum current is 550mA and the maximum start current is 500mA. 3. The typical operating current is 10 ~ 350mA, the overload detection current is 350 ~ 500mA. 4. Under no-load conditions, the maximum required current is 5mA. 5. Provide 3.84 ~ 12.95w: five levels of Electric Power requests, up to 13 W.
Serial Port server: Provides the serial port to the network function, can be RS-232/485/422 serial port into TCP/IP network interface, realize RS-232/485/422 serial port and TCP/IP network interface data two-way transparent transmission. This allows the serial device to immediately have the TCP/IP network interface function to connect to the network for data communication, greatly expanding the communication distance of the serial device. A networked server of a serial device is like a microcomputer with a CPU, real-time operating system, and TCP/IP protocol. It is convenient to transmit data between the serial port and network device (note: when wiring, the Tx header of the serial line is connected to the RX end of the Serial Server)

Serial Port wiring diagram:

Video pal NTSC: 24 video frames per second during film screening. The video image PAL system supports 50 videos per second, and the NTSC system supports 60 videos per second. Because current TVs are isolated from each other, we can probably think that the palsystem supports 25 complete video frames per second, NSTC generates 30 complete video frames. Bytes. Throttling allows the data receiving device to notify the data sending device when it cannot receive the data so that it stops sending the data. Serial Port throttling often uses two methods: hardware throttling and software throttling. J-link is a JTAG simulator launched by segger to Support Simulation of ARM Kernel chips.
Differences in use of JTAG and SWD: http://www.openedv.com/posts/list/187.htm

1. TCK (test clock)
2. TMS (test mode selection)