stm32f103 延时20ns,在STM32上生成C中的纳秒延迟

使用下面的stopwatch_delay(ticks)来完成延迟.它使用STM32的DWT_CYCCNT寄存器,该寄存器专门用于计算位于地址0xE0001004的实际时钟周期.

要验证延迟准确性(请参阅main),您可以调用STOPWATCH_START,运行stopwatch_delay(ticks),然后调用STOPWATCH_STOP并使用CalcNanosecondsFromStopwatch(m_nStart,m_nStop)进行验证.根据需要调整刻度.

uint32_t m_nStart; //DEBUG Stopwatch start cycle counter value

uint32_t m_nStop; //DEBUG Stopwatch stop cycle counter value

#define DEMCR_TRCENA 0x01000000

/* Core Debug registers */

#define DEMCR (*((volatile uint32_t *)0xE000EDFC))

#define DWT_CTRL (*(volatile uint32_t *)0xe0001000)

#define CYCCNTENA (1<<0)

#define DWT_CYCCNT ((volatile uint32_t *)0xE0001004)

#define CPU_CYCLES *DWT_CYCCNT

#define STOPWATCH_START { m_nStart = *((volatile unsigned int *)0xE0001004);}

#define STOPWATCH_STOP { m_nStop = *((volatile unsigned int *)0xE0001004);}

static inline void stopwatch_reset(void)

{

/*