Microsecond delay Delay_us in Stm32 cubemx HAL Project

Reference to the code of the punctual atom

Test Platform

Stm32f429i-disco

With a gpio.

Clock

Gpio

/*USER CODE BEGIN 0*/typedef uint8_t U8;TYPEDEF uint32_t u32;u8 fac_us;voiddelay_init (U8 sysclk) {#ifSystem_support_os//?????? OS.u32 Reload; #endifHal_systick_clksourceconfig (SYSTICK_CLKSOURCE_HCLK); //SysTick??? HCLKFAC_US=SYSCLK;//?????? Os,fac_us?????        #ifSystem_support_os//?????? OS.Reload=SYSCLK;//???????? ??? Kreload*=1000000/delay_ostickspersec;//?? delay_ostickspersec?????? //Reload????,??? : 16777216,? 180M?,?? 0.745s??fac_ms= +/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}voidDelay_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??????????.            Elsetcnt+=reload-tnow+told; Told=Tnow; if(tcnt>=ticks) Break;//???? /????????,???.        }    };}/*USER CODE END 0*/

intMainvoid){  /*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 ( -);    Hal_gpio_writepin (Gpiof, gpio_pin_7, Gpio_pin_reset); Delay_us ( -); /*USER CODE BEGIN 3*/  }  /*USER CODE END 3*/}

The actual test, the function call can bring hundreds of NS error.

Microsecond delay Delay_us in Stm32 cubemx HAL Project