static __INLINE uint32_t SysTick_Config(uint32_t ticks)
{
if (ticks > SYSTICK_MAXCOUNT) return (1); /* Reload value impossible */
SysTick->LOAD = (ticks & SYSTICK_MAXCOUNT) – 1; /* set reload register */
NVIC_SetPriority (SysTick_IRQn, (1<<__NVIC_PRIO_BITS) – 1); /* set Priority for Cortex-M0 System Interrupts */
SysTick->VAL = (0x00); /* Load the SysTick Counter Value */
SysTick->CTRL = (1 << SYSTICK_CLKSOURCE) | (1<ICK_ENABLE) | (1<ICK_TICKINT); /* Enable SysTick IRQ and SysTick Timer */
return (0); /* Function successful */
}
void SysTick_Initial(u16 periodtimer)
{
SysTick_Config(periodtimer);
SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK_Div8); // 分频放在装备后边，否则分频不起作用
}
