Posted on January 25, 2016 at 19:50Hi,
I have an issue with the STM32F429 (Discovery board with 8 MHz crystal).
I created a Keil project (software pack based) and added the following SW packs:
CMIS: Core
CMIS: DSP
Device: Startup
Then I added the following main file:
#include ''stdio.h''
#include ''stm32f4xx.h''
// PLL register values
#define PLL_MASK 0x80BC8000 // PLL register mask
#define PLLM_VAL 4 // PLL division factor
#define PLLN_VAL 180 // PLL multiplication factor
#define PLLP_VAL 0 // 0: div by 2
#define PLLSRC_VAL 1 // HSE is source to PLL
#define PLLQ_VAL 2 // PLLQ: not used
#define PLLR_VAL 2 // PLLR
int main(void){
RCC->CFGR = (RCC->CFGR & 0xFFFFFF0F); // AHB prescaler : 1
RCC->CFGR = (RCC->CFGR & 0xFFFFE3FF) | 0x1400; // APB1 prescaler: 4
RCC->CFGR = (RCC->CFGR & 0xFFFF1FFF) | 0x8000; // APB2 prescaler: 2
RCC->CR |= 0x10000;
while((RCC->CR & 0x20000) != 0x20000){ // wait for HSE ready
}
RCC->PLLCFGR = (RCC->PLLCFGR & PLL_MASK) | ((PLLR_VAL << 28) | (PLLQ_VAL << 24) | (PLLSRC_VAL << 22) | (PLLP_VAL << 16) | (PLLN_VAL << 6) | PLLM_VAL); // Setup PLL
RCC->CR |= 0x1000000; // Main PLL: ON
while((RCC->CR & 0x2000000) != 0x2000000){ // wait for PLL ready
}
RCC->CFGR = (RCC->CFGR & 0xFFFFFFFC) | 0x02; // PLL_P is selected as system clock
while((RCC->CFGR & 0x08) != 0x08){ // wait PLL_P to be used as system clock
}
RCC->CR = RCC->CR & 0xFFFFFFFE; // HSI oscillator disable
while(1){
}
}
But the CPU crashes after setting up the clocks. Any ideas?
Thank you.
