stm32 cubemx hal 工程中 微秒延迟 delay_us

参考的正点原子的代码

测试平台

stm32f429i-disco

配了一个gpio

时钟

gpio

/* USER CODE BEGIN 0 */
typedef uint8_t u8;
typedef uint32_t u32;u8 fac_us;void delay_init(u8 SYSCLK)
{#if SYSTEM_SUPPORT_OS //?????? OS.u32 reload;#endifHAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);//SysTick ??? HCLKfac_us=SYSCLK; //?????? OS,fac_us ?????#if SYSTEM_SUPPORT_OS //?????? OS.reload=SYSCLK; //???????? ??? Kreload*=1000000/delay_ostickspersec; //?? delay_ostickspersec ??????//reload ? 24 ????,???:16777216,? 180M ?,?? 0.745s ??fac_ms=1000/delay_ostickspersec; //?? OS ?????????SysTick->CTRL|=SysTick_CTRL_TICKINT_Msk;//?? SYSTICK ??SysTick->LOAD=reload; //? 1/OS_TICKS_PER_SEC ?????SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk; //?? SYSTICK#else#endif
}void delay_us(u32 nus)
{u32 ticks;u32 told,tnow,tcnt=0;u32 reload=SysTick->LOAD; //LOAD ??ticks=nus*fac_us; //??????told=SysTick->VAL; //?????????while(1){tnow=SysTick->VAL;if(tnow!=told){if(tnow<told)tcnt+=told-tnow;//???? SYSTICK ??????????.else tcnt+=reload-tnow+told;told=tnow;if(tcnt>=ticks)break; //????/????????,???.
        }};
}
/* USER CODE END 0 */

int main(void)
{/* USER CODE BEGIN 1 *//* USER CODE END 1 *//* MCU Configuration----------------------------------------------------------*//* Reset of all peripherals, Initializes the Flash interface and the Systick. */HAL_Init();/* Configure the system clock */SystemClock_Config();/* Initialize all configured peripherals */MX_GPIO_Init();/* USER CODE BEGIN 2 */delay_init(168);/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){/* USER CODE END WHILE */HAL_GPIO_WritePin(GPIOF, GPIO_PIN_7, GPIO_PIN_SET);delay_us(50);HAL_GPIO_WritePin(GPIOF, GPIO_PIN_7, GPIO_PIN_RESET);delay_us(50);/* USER CODE BEGIN 3 */}/* USER CODE END 3 */}

实际测试, 函数调用能带来几百ns的误差.