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Systick default clock setting for stm32f3discovery_fw

Question asked by spiezia.andrea on Oct 8, 2013
Latest reply on Oct 9, 2013 by Clive One

Hi all,

I’m starting to deal with STM32F30 discovery.
I need confirmation about my assertion on default clock configuration for the stm32f3discovery_fw.
In file system_stm32f30x.c the define PLL_SOURCE_HSE_BYPASS is uncommented
// HSE bypassed with an external clock (8MHz, coming from ST-Link) used to clock the PLL, and the PLL is used as system clock source

In this case the function SystemInit() calls the functions SetSysClock():

#elif defined (PLL_SOURCE_HSE_BYPASS)
  /* HSE oscillator bypassed with external clock */   
  RCC->CR |= (uint32_t)(RCC_CR_HSEON | RCC_CR_HSEBYP);

The same function sets HCLK = SYSCLK = PCLK2 = PCLK1 and PLLCLK = HSE * 9 = 72 Mhz and then Select PLL as system clock source, this meanse that HCLK =  72 Mhz

SysTick_Config() configure the SysTick Counter clock source to be Core Clock Source (HCLK).

At the end I understood that  SysTick Counter clock is  72 Mhz.

This means that SysTick_Config(SystemCoreClock / 1000) give an interrupts every 72000 clock cycle, that is an interrupt every 0.1 ms , is it correct?

Your support is very appreciate.

Thanks

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