I'm having trouble making the delay function in stm32f411vet. When the power frequency for the chip is 16MHZ, it still works normally but when the frequency is increased to about 64MHZ, the error occurs. Let me all ask you what fault this is.

I'm having trouble using STM32 to bind to the Webserver via the AT Command command. Connecting to the Webserver is fine, but the problem is that the site only runs a few times, the AT+CIPSEND command has a problem, data sent to ESP is 1 character err...