So why isn't the function called HalMinimumDelay()?.. (That's just a rhetorical question)In older implementations, this function was implemented as I previously expected.

I try to insert toggle command into interrupt..  1ms was OK.So problem is at implementation of "HAL_Delay(T)" function - T is (T+1).When I try HAL_Delay(2), time is 3ms.ST insert this code into HalDelay function: /* Add a freq to guarantee minimum w...

(It is not in the interrupt, but for this testing case it is same)

Yes. This is my test code: HAL_Delay(1); HAL_GPIO_TogglePin(WM_BUS_CS_GPIO_Port, WM_BUS_CS_Pin); HAL_Delay(1); HAL_GPIO_TogglePin(WM_BUS_CS_GPIO_Port, WM_BUS_CS_Pin); HAL_Delay(1); HAL_GPIO_TogglePin(WM_BUS_CS_GPIO_Port, WM_BUS_CS_Pin); ...

Here are registers:And PA8: clocksAnd main clock selection: