Recently capsize, absolutely did not expect the first time the serial port can not send normal data turned out to be because the problem CubeMX software settings.
In a recent project due to lack of materials, resulting in a number of boards a crystal oscillator 24Mhz and 8Mh two types of parameters, and write the program did not think, commissioning phase using a welding 24Mhz crystal board, everything OK, but in the after 24 clock configuration is not modified 8 on the board 8Mhz actually had BUG, the serial port can not send / receive data properly, the first thought is the baud rate, in fact, is the clock, but did not think that is the establishment of engineering problems using CubeMx , finally come up with questions prior to the establishment of 8MHz template to solve.
Due to the time, yet it is where to go to troubleshoot specific problems caused by modified setting is not correct, but still want a word of warning, the more simple tools, may cause incredible bug.