There may be the following reasons:
< br >
1. Burning equipment failure: there may be hardware failure or software failure of the burning equipment, resulting in poor burning.
< br >
2. Improper setting of burning parameters: incorrect setting of burning parameters, such as improper setting of burning clock frequency, burning voltage, etc., will lead to poor burning.
< br >
3. IC quality problems: There are quality problems in the IC itself, such as memory unit damage, poor pin contact, etc., which will lead to poor burning.
< br >
4. PCB board design problems: Unreasonable PCB board design, such as poor wiring, power supply noise and other problems, will lead to poor burning.
< br >
5. Environmental factors: the burning environment temperature, humidity and other factors will also affect the burning quality, such as high temperature or humidity, will lead to poor burning.
< br >
6. Technical problems of the operator: the operator is not skilled or non-standard, such as incorrect burning operation, non-standard operating process, etc., which will lead to poor burning.
It shall be dealt with separately according to the specific circumstances.
< br >
1. There is no power loss!! If there is no automatic power off circuit, you need to manually power off;
< br >
2. Whether the crystal oscillator of the single chip microcomputer is installed properly, whether there is any missing, and whether the load capacitor of the crystal oscillator is suitable;
< br >
3. The TXD and RXD of the CH340 must be inversely connected to the TXD and RXD of the microcontroller. Is the ground cable of the CH340 properly connected to the microcontroller?
< br >
4. If the smallest system of the single chip microcomputer is welded by itself, check the reset circuit, whether the RST pin level has been pulled high because of the problem of the reset circuit;
< br >
5. Confirm whether the model of the microcontroller is correct and try to reduce the baud rate of the download.