STC microcontroller burning problem

You may start learning about STC microcontrollers, because they can be directly programmed without any programmer, but I have seen some people encounter problems when programming. I often see people asking for help with such problems on forums and Zhidao.com. Their answers are generally about whether the serial port driver is installed, whether the model is selected correctly, whether the cold start is successful, etc. In fact, the real reason for not being able to program is not because of these problems. According to my summary, the possible reasons are as follows:

1. The influence of circuit noise. Many people like to burn on the development board when burning. In fact, when burning, the development board only provides the function of a minimum system board, but often there are more than the circuits of the minimum system board on the development board, which may introduce some noise. I can't tell how much influence these noises have, but I suspect that it will still affect the success rate of burning. I suggest burning with a downloader. The circuit shown in the figure is simple and reliable, but pay attention to adding capacitors.

2. Components. The quality of the original circuit components is related to the quality of the oscillation circuit, and the oscillation circuit is the basis for the operation of the single-chip microcomputer. As shown in the figure, it is recommended to use 11.0592MHz crystal oscillator and good quality monolithic capacitors.

3. Software. You can try multiple baud rates on the software. If there is a problem with the software, you can judge it by the following. First of all, it is recommended to use a downloader similar to the following. Why? As you can see, there is a data indicator on it. When you select the file on the software interface and click to download, if the TXD indicator does not flash, it means that there is a problem with the software, because the download process of the STC microcontroller is like this. After the microcontroller is powered on, it automatically detects whether the microcontroller RXD has a download signal. If so, download the program. If not, execute the original program of the microcontroller. If the TXD indicator on the downloader does not flash, it means that the computer has not sent a download instruction at all, indicating that the download software may be wrong and needs to be reinstalled, or the driver is not installed properly. But it is not necessarily all software errors. As you know, the downloader is not like a USB flash drive. You can click to safely delete the hardware, and the downloader can only be hard pulled. This process may generate a large current, and the USB interface inside the computer has a self-recovery fuse. Therefore, this fuse is easier to break. You may need to wait for a while or change the USB interface.

3. The reset time is too long. In order to ensure the reliability of the reset circuit, the current minimum system board or development board often has a long reset time. I guess it is because of this that the microcontroller misses the time to automatically detect whether to download after power-on, and you cannot download the program no matter how you cold start. Therefore, I still recommend the connection method shown in the figure above, without connecting the reset circuit. According to my experience, not connecting the reset circuit has no effect on downloading.

4. Hand touch introduces noise. When I was doing experiments on the development board, sometimes my fingers touched the oscillation circuit, and the microcontroller would freeze or reset. It can be seen that the oscillation circuit is quite fragile. Therefore, when downloading the program, be sure not to touch the oscillation circuit.

The above suggestions are purely based on the author's experience, because I am not specialized in this. I am just a person who plays with microcontrollers like everyone else. I have encountered some problems before, and I didn't expect that everyone would encounter them too, so I share the solutions with everyone. The above theory is purely speculation and has no academic reference value.