HAL_Delay(). this function implements a delay (expressed in milliseconds) using the
HAL_Delay(). this function implements a delay (expressed in milliseconds) using the
SysTick timer.
Care must be taken when using HAL_Delay() since this function provides an accurate
delay (expressed in milliseconds) based on a variable incremented in SysTick ISR.
This means that if HAL_Delay() is called from a peripheral ISR, then the SysTick
interrupt must have highest priority (numerically lower) than the peripheral interrupt,
otherwise the caller ISR will be blocked.