void init_HW(void)
{
RCC->CR |= RCC_CR_MSION; // Turn on MSI
// Reset SW[1:0], HPRE[3:0], PPRE1[2:0], PPRE2[2:0], MCOSEL[2:0] and MCOPRE[2:0] bits
RCC->CFGR &= ~(RCC_CFGR_SW | RCC_CFGR_HPRE | RCC_CFGR_PPRE1 | RCC_CFGR_PPRE2 | RCC_CFGR_MCOSEL | RCC_CFGR_MCO_PRE);
// Reset HSION, HSIDIVEN, HSEON, CSSON and PLLON bits
RCC->CR &= ~(RCC_CR_HSION | RCC_CR_HSIDIVEN | RCC_CR_HSEON | RCC_CR_CSSHSEON | RCC_CR_PLLON);
// Reset HSI48ON bit
RCC->CRRCR &= ~RCC_CRRCR_HSI48ON;
// Reset HSEBYP bit
RCC->CR &= ~RCC_CR_HSEBYP;
// Reset PLLSRC, PLLMUL[3:0] and PLLDIV[1:0] bits
RCC->CFGR &= ~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL | RCC_CFGR_PLLDIV);
// Disable all interrupts
RCC->CIER = 0;
InitClocks();
// enable IOPx peripheral
RCC->IOPENR |=
RCC_IOPENR_GPIOAEN |
RCC_IOPENR_GPIOBEN |
RCC_IOPENR_GPIOCEN |
RCC_IOPENR_GPIODEN |
RCC_IOPENR_GPIOHEN;
}
void LED_InitGPIO(void)
{
RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
GPIO_InitTypeDef gpioInit = {
.GPIO_Pin = 0,
.GPIO_Mode = GPIO_Mode_OUT,
.GPIO_OType = GPIO_OType_PP,
.GPIO_PuPd = GPIO_PuPd_UP,
.GPIO_Speed = GPIO_Speed_50MHz
};
for(int j = 0; j < 4; ++j) {
gpioInit.GPIO_Pin = LED_PIN[j];
GPIO_Init(LED_PORT[j], &gpioInit);
}
}
void SetLED(int led, bool state) {
if(state)
LED_PORT[led]->BSRRL = LED_PIN[led];
else
LED_PORT[led]->BSRRH = LED_PIN[led];
}
void ToggleLED(int led) {
LED_PORT[led]->ODR ^= LED_PIN[led];
}
static void InitClocks(void);
// static void TIM4_Config(void);
int main(void)
{
InitClocks();
// Configure for millisecond system ticks
if(SysTick_Config(SystemCoreClock/1000))
while(1) {;}
LED_InitGPIO();
SetLED(0, true);
SetLED(1, true);
int led = 0;
while(1)
{
delay_ms(1);
ToggleLED(led);
led = (led + 3)%4;
}
} // main()
