void reset_handler(void)
{
/* Copy the data segment initializers from flash to SRAM */
uint32_t *idata_begin = &_sidata;
uint32_t *data_begin = &_sdata;
uint32_t *data_end = &_edata;
while (data_begin < data_end) *data_begin++ = *idata_begin++;
/* Zero fill the bss segment. */
uint32_t *bss_begin = &_sbss;
uint32_t *bss_end = &_ebss;
while (bss_begin < bss_end) *bss_begin++ = 0;
/* Clock system intitialization */
rcc_clock_init();
main();
}
int main(void)
{
rcc_clock_init();
/* Set PA8 for MCO1 function */
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
GPIOA->MODER = GPIO_MODER8_ALTERNATE;
GPIOA->OTYPER = GPIO_OTYPER8_PP;
GPIOA->OSPEED = GPIO_OSPEED8_100MHZ;
GPIOA->PUPDR = GPIO_PUPDR8_NO;
GPIOA->AFRH = GPIO_AFRH8_AF0;
/* Set PC9 as MCO2 function */
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOCEN;
GPIOC->MODER = GPIO_MODER9_ALTERNATE;
GPIOC->OTYPER = GPIO_OTYPER9_PP;
GPIOC->OSPEED = GPIO_OSPEED9_100MHZ;
GPIOC->PUPDR = GPIO_PUPDR9_NO;
GPIOC->AFRH = GPIO_AFRH9_AF0;
/* Set MCO1, depends on which rcc you used */
init_mco1();
/* Set MCO2, select SYSCLK as output source and no division */
RCC->CFGR &= ~RCC_CFGR_MCO2;
RCC->CFGR |= RCC_CFGR_MCO2_SYSCLK;
RCC->CFGR &= ~RCC_CFGR_MCO2_PRE;
RCC->CFGR |= RCC_CFGR_MCO2_PRE_DIV1;
/* Set PG13 as general output function(LED) */
RCC->AHB1ENR |= RCC_AHB1ENR_GPIOGEN;
GPIOG->MODER = GPIO_MODER13_OUTPUT;
GPIOG->OTYPER = GPIO_OTYPER13_PP;
GPIOG->OSPEED = GPIO_OSPEED13_100MHZ;
GPIOG->PUPDR = GPIO_PUPDR13_NO;
/* Set SysTick, trigger every 500ms */
init_systick();
while(1);
return 0;
}
