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HSI and GPS interference

Question asked by mbavaro on Jun 28, 2012
Latest reply on Jun 28, 2012 by Clive One
Hello everyone,

Did anyone notice that STM32 with an internal HSI at 8MHz cannot be used in proximity to an embedded GPS antenna? The 8MHz internal oscillator happens to have the 197th harmonic close to L1 and interferes with the GPS antenna element.
Am I correct guessing that adding the following code

/* MICHELE: Disable noisy 8MHz internal oscillator */
RCC->CR &= ~RCC_CR_HSION;

in system_stm32f10x.c after 

/* Wait till PLL is used as system clock source */
while ((RCC->CFGR & (uint32_t)RCC_CFGR_SWS) != (uint32_t)0x08)
{
}

should improve?

Best regards,
Michele

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