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#include "rcc.h"
#include "flash.h"
void rcc_init() {
// Initialize flash.
flash_init();
#if defined(STM32F1) || defined(STM32F3)
// Enable HSE.
RCC.CR |= 0x10000;
while(!(RCC.CR & 0x20000));
// Configure and enable PLL.
RCC.CFGR = (4 << 18) | (1 << 16); // PLLMUL = x6, PLLSRC = HSE
RCC.CR |= 0x1000000;
while(!(RCC.CR & 0x2000000));
// Switch to PLL.
RCC.CFGR |= 0x2;
while(!(RCC.CFGR & 0x8));
// Set APB1 prescaler to /2.
RCC.CFGR |= 0x400;
// Set ADCCLK prescaler to /6.
RCC.CFGR |= 0x8000;
#elif defined(STM32F4)
// Enable HSE.
RCC.CR |= 0x10000;
while(!(RCC.CR & 0x20000));
// Configure and enable PLL.
RCC.PLLCFGR = 0x20400000 | (7 << 24) | (2 * 168 << 6) | 8;
RCC.CR |= 0x1000000;
while(!(RCC.CR & 0x2000000));
// Switch to PLL.
RCC.CFGR |= 0x2;
while(!(RCC.CFGR & 0x8));
// Set APB1 prescaler to /4.
RCC.CFGR |= 5 << 10;
// Set APB2 prescaler to /2.
RCC.CFGR |= 4 << 13;
#endif
}
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