MM32F MCUs delay in ms(milli seconds) and us(microseconds)

static u8 fac_us = 0;

 static u16 fac_ms = 0;

 extern u32 SystemCoreClock;

 void delay_init() 

{ 

 SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8);

 fac_us = SystemCoreClock / 8000000;

 fac_ms = (u16)fac_us * 1000; } void delay_us(u32 nus) { u32 temp; SysTick->LOAD = nus * fac_us; SysTick->VAL = 0x00; SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk ; do { temp = SysTick->CTRL; } while((temp & 0x01) && !(temp & (1 << 16))); SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk; SysTick->VAL = 0X00; } void delay_ms(u16 nms) { u32 temp; SysTick->LOAD = (u32)nms * fac_ms; SysTick->VAL = 0x00; SysTick->CTRL |= SysTick_CTRL_ENABLE_Msk ; do { temp = SysTick->CTRL; } while((temp & 0x01) && !(temp & (1 << 16))); SysTick->CTRL &= ~SysTick_CTRL_ENABLE_Msk; SysTick->VAL = 0X00; }