Online programming is favored by many users because of its advantages of integrating programming and testing, but it is often caused by too long wiring due to connection tooling and fixtures, which in turn increases instability and programming failure rate. How to improve this?
1. Increase the shielding layer to prevent electromagnetic interference and electrostatic interference
As a tool that closely communicates with the chip, the programmer is more sensitive to electromagnetic interference. The programming environment is generally a factory workshop, and high-power equipment makes electromagnetic interference more serious. In order to reduce electromagnetic interference, we can add a shielding net to the programming line, or choose a line with a shielding function, such as a shielded cable, network cable, etc. In addition, It is best to wear electrostatic gloves during operation to prevent electrostatic interference.
2. Choose a wire with strong conductivity
The integrity of signal transmission is related to the material, length, and thickness of the wire. You can choose thicker, more conductive wires. Good materials can reduce internal resistance and signal loss, such as pure copper wires, gold-plated wires, and silver-plated wires. line etc.
3. Reduce communication frequency
Communication frequency is an important parameter for information transmission. The higher the frequency, the faster the transmission speed, but the attenuation of the signal will increase with the increase of the frequency, and it will weaken rapidly with the increase of the transmission distance. Therefore, when the wiring is long, it can be properly Reduce communication frequency to increase communication stability.
4. Connect pull-up or pull-down resistors on key signal lines
The programming interface of some chips has weak driving ability, and it is necessary to add appropriate pull-up or pull-down resistors to the interface to enhance the driving ability. For example, IIC and SWIM interfaces need to connect strong pull-up resistors on the data lines, and the car key chip PCF79xx , NCF29xx, etc. need to connect pull-down resistors on the clock line, etc. the best programmer for car key chip PCF79xx , NCF29xx, is SmartPRO 5000U-Plus and T9000 Plus. Choose the correct programmer, the work will be more easy and fast.
5. Choose a programmer with strong drive capability
The driving ability of the programmer pins will directly affect the length of the wiring. Some online programmers on the market directly lead to the IO port of the internal control chip or the pins of the FPGA as the input and output of the programming signal, and their driving ability is relatively low. Weak, when the user’s wiring is relatively long (generally greater than 30cm), signal distortion will occur, resulting in unstable programming.
When choosing a programmer, you need to choose a professional online programmer, such as the P800isp programmer from ZLG Zhiyuan Electronics. Through multi-channel signal enhancement processing, the drive capability of the programmer is increased, and a series of problems caused by too long wiring are solved.
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