Problems with heating and resetting of STC microcontrollers

Recently, I have a project that requires a relay that will work when it receives a low level. I use STC15W104 and a 5V/3A switching power supply on the market.

Something that seemed simple at first took me nearly three days to complete.

1. Phenomenon 1

The product is an ARM motherboard inside a 1U chassis, which needs to be hard restarted at regular intervals. Let's call it the STC control board. When the control board is not loaded, it triggers normally and is in line with the program. However, after loading, the first trigger is normal, but the second time the microcontroller starts to heat up, reaching more than 80 degrees, and then smokes directly. This phenomenon will 100% occur. The relay of the control board is not isolated.

Solution:

I connected a 1000UF capacitor to the 5V power supply. I tried to connect a 5.1V voltage regulator, but it didn't work.

2. Phenomenon 2

The board will malfunction, especially if there are people around, or if it has been working for a while, or if the switch 963 soldering iron can cause the relay to trigger malfunction.

Solution:

Modify the program's detection and add a debouncing operation (20ms delay); remove the "allow low-voltage reset" of the downloader. This will cause a low-voltage interrupt. No detection is performed (you can add a program to verify it yourself, but I don't have time to test it). I feel that this is very likely, that is, the surrounding environment caused the microcontroller to reset.

The above are some of my personal debugging experiences. I share them with you and hope that they can be useful to others.