"During installation and production, the STM32F103RCT6 chip can work normally. However, after the finished machine is delivered to the customer, the STM32F103RCT6 chip is burned and damaged.
The signal line in the communication interface between the finished machine and the client is directly connected to the I/O port of the chip. The client and the finished machine are used together. When the output line of the finished machine is abnormal (later found to be STM32F103RCT6 chip burnt), the client does not have a chip burnout.
The relevant directly connected pins are [PB3] & [PB4], PB3 is used as the output I/O quantity, and PB4 is used as the input I/O quantity.
What are the possible reasons for the chip burning?"
Large differences in potential, and current flow ?
You've created a conduction path through the IC, and it's acted like a fuse.
Check that grounds between board are suitably bonded before introducing other signals.
