Now more people pay attention to the online programming that integrates programming and testing. In order to improve the efficiency of programming, some fixtures and programming tools are usually made. Long wiring is required between fixture, tooling and programmer, and the length of wiring will affect the signal transmission strength. Generally speaking, the longer the wiring, the weaker the signal. When the signal is weak, the defective programming rate also increases. So how to solve the problem of instability in the programming process of the programmer?
The first is to increase the shielding layer to prevent electromagnetic interference; as a tool to maintain close communication with the programming chip, the programmer is very sensitive to electromagnetic interference. The programming application environment is generally a factory floor, but high-power equipment can make electromagnetic interference more serious. In order to reduce the degree of interference as much as possible, you can add a shielding network to the programming line, or directly use a shielded cable, such as shielded network cable, cable, etc. In addition, it is best to wear electrostatic gloves during operation to prevent interference.
The second is to choose a wire with relatively strong conductivity. Generally speaking, a thicker wire should be selected. The length, thickness and material of the wire will affect the electrical integrity of the signal transmission. Choosing a good material can reduce internal resistance and signal loss. Commonly used are pure copper wire, silver-plated wire, gold-plated wire, etc.
There is also to reduce the frequency of communication. Communication frequency is an important reference data for information transmission. The higher the frequency, the faster the transmission speed, but the increase in frequency will also weaken the signal. Therefore, when the wiring is relatively long, the communication frequency can be appropriately reduced to increase the stability of the communication.
In addition, a resistor can be connected to the signal line. The programming interface of some chips has a weak driving ability, and a pull-down resistor can be connected to the interface to enhance the driving force. Of course, you can also choose a programmer with strong driving ability. The driving ability of the programmer directly affects the length of the wiring. There are online programmers on the market, which directly lead to the IO port of the internal control chip or FPGA pins as the output and Input, if the driving ability is weak, the signal will be distorted when the wiring is relatively long, resulting in unstable programming. The processing method is multi-channel signal enhancement, increasing the driving capability of the programmer, and solving the problem of excessively long wiring.
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