Hello Everybody
I started using Nucleo-F401RE (MB1136 C-04) a few months ago and I am trying to understand how work the SystemInit() function and the clock setting.
As IDE, I use SystemWorkbench/AC6.
When I start a new project using HAL or LL drivers, the system_stm32f4xx.c file which is loaded uses a simple SystemInit() function which sets HSI on and uses it ; it is fairly clear.
But if I start a new project using SPL (standard peripheral lib), the system_stm32f4xx.c file which is then loaded uses a SystemInit() function which calls a SetSyssClock() function.
- At the beginning of the SystemInit() function, the HSI is set on, OK.
- But then in SetSyssClock() function, the HSE is also set on.
- Then when I run/debug the prog, I see in the RCC_CR register that both HSION and HSEON are set ; so I understand no more ! Which clock is then used to drive the system, or better to feed the PLL ?
Can someone tells me where can I find basic documentation about the setting of the clock on a such board ? I read the official doc and search the internet but do not find anything very clear.
Thank you inadvance
Jack-Michel CORNIL
P.S. sorry if my english is not correct but I am french !
