What is the equation to calculate the FDCAN clock on STM32H743xx?

[bassem.saleh93]

I know its clock is provided from the APB1, but I can't figure out how to calculate and what are the relations between fdcan_ker_ck and fdcan_pclk

[bassem.saleh93]

Ok guys, I figured it out.

fdcan_ker_clk is associated with PLL1Q (you can choose this by this command):

RCC_PeriphCLKInitTypeDef RCC_PeriphClkInit;
 
RCC_PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_FDCAN;
RCC_PeriphClkInit.FdcanClockSelection = RCC_FDCANCLKSOURCE_PLL;

The PLL1Q is given by = PLLclocksource * DIVN1 / (DIVM1 * DIVQ1)

For a HSE oscillator running at 8 MHz

Choosing DIVN1=400

DIVM1 = 4

DIVQ1 = 40

we will get that FDCAN clock is 20 MHz

Hope this helps