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STM32F407 with a 50.0MHz Oscillator

Question asked by Evelyn Sabbag on Mar 20, 2018
Latest reply on Mar 21, 2018 by redwire

I am running an STM32F407 with an ECS-2033-500BN Oscillator (50.0MHz) to accommodate the MCU and the ETH off the same oscillator. The circuit uses a fanout buffer to distribute the clock. Nowhere can I find information on how to configure the STM32F4 system clock with this high of a value (I assume there's a divide by 2 enabled in the bowels of the MCU) and the Clock Configuration tool doesn't help. Any suggestions? And yes, I've looked through the forum and the datasheet and I haven't been able to get the circuit to run.


I know the circuit works because previous FW was developed using NuTTx. I am porting the code to IAR and am stuck at the PLL initialization in the generated file system_stm32f4xx.c at the line: 


/* Wait till the main PLL is ready */
while((RCC->CR & RCC_CR_PLLRDY) == 0)


Any help would be greatly appreciated.