Solution to Handshake Failure during ISP Download of STC MCU

I encountered a very frustrating problem today. When downloading the HEX file to the microcontroller, although the microcontroller information, such as the main frequency, etc., can be detected, the teacher prompted that the handshake failed during the download.

I checked a lot of information, but still couldn't solve this problem. Because I use a laptop, I can only use a USB to serial cable. I used this and the serial conversion cable before and didn't have this problem, so I began to suspect that it was a software problem, but I installed and uninstalled, uninstalled and installed, tried N versions but still had this problem, I was really going to collapse.

This made me start to suspect that it was not a software problem. I saw on the Internet that I should lower the maximum download baud rate. I lowered the minimum baud rate to 57600 and 2400, but the problem still occurred. I thought about it for a long time but still couldn't figure it out. Just when I was about to give up, I tried changing both the maximum and minimum baud rates to 1200, the lowest baud rate. It actually worked. I was really delighted. Even though the speed was slower, at least I could still download successfully. I was really happy.

Then I tried to increase the baud rate, and found that the download could not be successful when it reached 9600. So I used two 4800s to download the program. The speed was faster and it also solved the problem of handshake failure.

I still don't know exactly where the problem is, but I know how to solve it anyway. Maybe it's a software problem, or maybe it's a serial port conversion cable problem. Anyway, if you have the same problem, you might as well give it a try, maybe you can find a way out!!!