Our products use STM32F103+CC2564C for FCC certification conduction test, and the tool uses HCITester. We tested 10 samples, and 5 samples have problems with the fixed frequency output. For example, my fixed frequency is 2402MHz, and the actual measurement is 2403.xx Mhz, I tried to exchange the normal and abnormal product 26M crystal oscillator, but the problem still exists, it has nothing to do with the crystal oscillator, I have tested each crystal oscillator, and the error is within 10 PPM.
What might be the cause of such a problem?
