The STM32 board suddenly had a big problem. So the delay function is 9 times slower.
My delay function is the exact delay of the SysTick function.
Because the first step requires initialization time, the general 8M crystal oscillator must be initialized 72. Because the system is generally 9 times the frequency multiplier.
But today it seems that the system is not multiplied by 9 times.
Therefore, the overall time is 9 times longer.
Later I found that the multiplier is
RCC_HSEConfig(RCC_HSE_ON);
HSEStartUpStatus = RCC_WaitForHSEStartUp();
If(HSEStartUpStatus == SUCCESS)
If it is set after success, if HSEStartUpStatus is not equal to 1, then the multiplier will not be executed. In other words, you can only use the 8M crystal that comes with the internal.
After a single step, I found that this HSEStartUpStatus is always 0. That is, the external crystal has not been checked.
So we started to see if the crystal oscillator did not start.
Using an oscilloscope, it is determined that the crystal does not start.
So is the crystal problem or the board problem?
The previous circuit has always been so expensive, and there have been no problems.
There is still a problem with changing a crystal.
Is it a capacitor problem?
Previously, 22P capacitors were used.
So it would be nice to switch to 20P.
Still a bit puzzled, in theory, the capacitor should not have such a big impact.
But the problem is solved.
I hope that if you encounter the same problem, you can try to change the capacitor.
Analysis of the reason why the crystal oscillator does not vibrate:
(1) PCB board wiring error;
(2) There is a problem with the quality of the single chip microcomputer;
(3) There is a problem with the quality of the crystal oscillator;
(4) The load capacitor or matching capacitor does not match the crystal oscillator or the capacitor quality is faulty;
(5) The PCB board is damp, resulting in impedance mismatch and failure to start vibration;
(6) The trace of the crystal oscillator circuit is too long.
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