panda/board/stm32fx/clock.h

40 lines
1.2 KiB
C

void clock_init(void) {
// enable external oscillator
register_set_bits(&(RCC->CR), RCC_CR_HSEON);
while ((RCC->CR & RCC_CR_HSERDY) == 0);
// divide things
register_set(&(RCC->CFGR), RCC_CFGR_HPRE_DIV1 | RCC_CFGR_PPRE2_DIV2 | RCC_CFGR_PPRE1_DIV2, 0xFF7FFCF3U);
// 16mhz crystal
register_set(&(RCC->PLLCFGR), RCC_PLLCFGR_PLLQ_2 | RCC_PLLCFGR_PLLM_3 | RCC_PLLCFGR_PLLN_6 | RCC_PLLCFGR_PLLN_5 | RCC_PLLCFGR_PLLSRC_HSE, 0x7F437FFFU);
// start PLL
register_set_bits(&(RCC->CR), RCC_CR_PLLON);
while ((RCC->CR & RCC_CR_PLLRDY) == 0);
// Configure Flash prefetch, Instruction cache, Data cache and wait state
// *** without this, it breaks ***
register_set(&(FLASH->ACR), FLASH_ACR_ICEN | FLASH_ACR_DCEN | FLASH_ACR_LATENCY_5WS, 0x1F0FU);
// switch to PLL
register_set_bits(&(RCC->CFGR), RCC_CFGR_SW_PLL);
while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL);
// *** running on PLL ***
}
void watchdog_init(void) {
// setup watchdog
IWDG->KR = 0x5555U;
register_set(&(IWDG->PR), 0x0U, 0x7U); // divider/4
// 0 = 0.125 ms, let's have a 50ms watchdog
register_set(&(IWDG->RLR), (400U-1U), 0xFFFU);
IWDG->KR = 0xCCCCU;
}
void watchdog_feed(void) {
IWDG->KR = 0xAAAAU;
}