AnsweredAssumed Answered

How to figure out my clock and pll clock ?

Question asked by mccarty.michael on Nov 11, 2014
Latest reply on Nov 11, 2014 by tereniev.oleg
Hello All, and Clive,
   I've went back into the guts of my program after a long time being out of it, and I dont know how I can know the actual clock speed of my unit. I dont have a scope that does more than 1Mhz.

   I'm using a stm32f4 discovery board. 407VT I think.

In project options I have Xtal 8Mhz

In system_stm32f4xx.c I have

/* PLL_VCO = (HSE_VALUE or HSI_VALUE / PLL_M) * PLL_N */
#define PLL_M      16
#define PLL_N      336
 
/* SYSCLK = PLL_VCO / PLL_P */
#define PLL_P      2
 
/* USB OTG FS, SDIO and RNG Clock =  PLL_VCO / PLLQ */
#define PLL_Q      7

uint32_t SystemCoreClock = 168000000;

So I assume my board is running at 168Mhz. Then I have a clock signal for a camera that is setup like this

RCC_MCO1Config(RCC_MCO1Source_PLLCLK, RCC_MCO1Div_5);

So is my MC01 output running at 168/5 = 33.6Mhz ? Or is the PLL clock different from my system clock.

Thanks as always for your time.

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