I am triying to change the stm32f407 systeme core clock to be 100MHz. To do this I need to set the source of the PLL to be HSE, and configure the PLL coefficient so as to get the right value of SYSCLK.
Here a screenshot of the stmcube that chows the right values of pll M, N, P, Q.
Here is my function
void rcc_clk_config() // function to configure the rc clk for running on HSE : sysclk at 100MHZ
{
RCC_PLLConfig(RCC_PLLSource_HSE, 4, 200, 4, 4);//sysclck to 100mhz , systick to 12.5 mhz
RCC_HCLKConfig(RCC_SYSCLK_Div1);
RCC_PCLK1Config(RCC_HCLK_Div4);
RCC_PCLK2Config(RCC_HCLK_Div2);
do{
RCC_HSEConfig(RCC_HSE_ON);;
}
while(RCC_GetFlagStatus(RCC_FLAG_HSERDY)!=SET);
do{
RCC_PLLCmd(ENABLE);
}
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY)!=SET);
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
SystemCoreClockUpdate();
}
In the debug session I get SystemCoreClock = 57.600.000.
Edit: it works now, here is the new code
{
RCC_DeInit();
do{
RCC_HSEConfig(RCC_HSE_ON);
}
while (!RCC_WaitForHSEStartUp());
RCC_PLLConfig(RCC_PLLSource_HSE, 4, 200, 4, 4);//100MHZ
do{
RCC_PLLCmd(ENABLE);
}
while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY)!=SET);
RCC_HCLKConfig(RCC_SYSCLK_Div1);
RCC_PCLK1Config(RCC_HCLK_Div4);
RCC_PCLK2Config(RCC_HCLK_Div2);
RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK);
SystemCoreClockUpdate();
}