AnsweredAssumed Answered

STM32F746 CubeMX clock not reporting correctly?

Question asked by Jeremy Vance on Oct 25, 2017
Latest reply on Oct 25, 2017 by Clive One

I'm using an STM32F746VGT6 microcontroller configured from STM32CubeMX for all the clocks and I'm getting roughly 220% higher clock rates reported for SystemCoreClock when compiled. For instance I have an HSE crystal at 11.2896MHz with the following main PLL settings:

PLLM /11
PLLN *234
I have selected HSE for PLL source and PLLCLK as System Clock Source. Doing that in STM32CubeMX yields 120.080291MHz. 
However, after SystemClock_Config(), SystemCoreClock = 265909059. 
Due to that discrepancy, the microcontroller thinks it's working 220% faster than it actually is so all my timings are off by that much.

My first clue was when I configured SAI_BlockA1 and measured MCLK to be double than expected.  Then testing an output with HAL_Delay(50) gave me actual delay of 110ms.

Has anyone else seen this issue and what could be the problem here? Thanks for any insight.