The serial assistant sscom32 can receive the data sent by stm32, indicating that the number sent by stm32 is normal. If HyperTerminal and putty can't receive it, find the reasons from the following three points.

1, check the baud rate, parity, stop bit setting and hardware-free flow control setting of HyperTerminal.

2. HyperTerminal can only display characters or Chinese characters. If stm32 sends hexadecimal numbers (that is, hexadecimal codes), HyperTerminal can receive them, but cannot display them. Let stm send a string to try.

3. When setting up an open HyperTerminal, you need to select the serial number, namely COMn, and check whether the serial number N is correct.