uC/OS 时间戳和时间戳的使用

声明：所有uC/OS代码均来自于官方uC/OS内核

关于时间戳，首先要明白一点：时间戳是一个计数器，且记录的是内核的HCLK运行的个数。

看代码

时间戳（time stamp）即TS.

时间戳的初始化代码在函数void  CPU_Init (void)；

#define  DEF_DISABLED                                      0u
#define  DEF_ENABLED                                       1u

#if    ((CPU_CFG_TS_32_EN == DEF_ENABLED) || \
        (CPU_CFG_TS_64_EN == DEF_ENABLED))
#define  CPU_CFG_TS_EN                          DEF_ENABLED
#else
#define  CPU_CFG_TS_EN                          DEF_DISABLED
#endif


void  CPU_Init (void)
{
                                                         
#if ((CPU_CFG_TS_EN     == DEF_ENABLED) || \
     (CPU_CFG_TS_TMR_EN == DEF_ENABLED))

    CPU_TS_Init();                                           
#endif
……
}

时间戳的初始化:CPU_TS_Init();

#if ((CPU_CFG_TS_EN     == DEF_ENABLED) || \
     (CPU_CFG_TS_TMR_EN == DEF_ENABLED))
static  void  CPU_TS_Init (void)
{
#if (((CPU_CFG_TS_32_EN    == DEF_ENABLED     )  && \
      (CPU_CFG_TS_TMR_SIZE <  CPU_WORD_SIZE_32)) || \
     ((CPU_CFG_TS_64_EN    == DEF_ENABLED     )  && \
      (CPU_CFG_TS_TMR_SIZE <  CPU_WORD_SIZE_64)))
    CPU_TS_TMR  ts_tmr_cnts;
#endif


                                                                /* ----------------- INIT CPU TS TMR ------------------ */
#if (CPU_CFG_TS_TMR_EN == DEF_ENABLED)
    CPU_TS_TmrFreq_Hz   = 0u;                                   /* Init/clr     ts tmr freq (see Note #1a).             */
	/*时间戳定时器初始化函数*/
    CPU_TS_TmrInit();                                           /* Init & start ts tmr      (see Note #1b).             */
#endif

……

}

继续深入void  CPU_TS_TmrInit (void)；

#if (CPU_CFG_TS_TMR_EN == DEF_ENABLED)
void  CPU_TS_TmrInit (void)
{
    CPU_INT32U  fclk_freq;


    fclk_freq = BSP_CPU_ClkFreq();//获取HCLK频率HCLK_Frequency
		/*启用DWT外设*/
    CPU_REG_DEM_CR     |= (CPU_INT32U)CPU_BIT_DEM_CR_TRCENA;    /* Enable Cortex-M4's DWT CYCCNT reg.                   */
    CPU_REG_DWT_CYCCNT  = (CPU_INT32U)0u;//清理DWT cyccnt
	/*当使用硬件全速运行时，会先停在这里，需要手动运行才能跳过，但是当使用硬件仿真时却不会*/
	
    CPU_REG_DWT_CR     |= (CPU_INT32U)CPU_BIT_DWT_CR_CYCCNTENA;// 启用Cortex-M4's DWT CYCCNT寄存器

    CPU_TS_TmrFreqSet((CPU_TS_TMR_FREQ)fclk_freq);
}
#endif

首先DWT(Data Watchpoint and Trace)作用为使能DWT CYCCNT reg，即使能CYCCNT寄存器

然后清零    CPU_REG_DWT_CYCCNT  = (CPU_INT32U)0u;

再启用Cortex-M4's DWT CYCCNT寄存器 

CPU_REG_DWT_CR     |= (CPU_INT32U)CPU_BIT_DWT_CR_CYCCNTENA;

然后获取HCLK频率HCLK_Frequency fclk_freq = BSP_CPU_ClkFreq();

CPU_INT32U  BSP_CPU_ClkFreq (void)
{
    RCC_ClocksTypeDef  rcc_clocks;

    RCC_GetClocksFreq(&rcc_clocks);
    return ((CPU_INT32U)rcc_clocks.HCLK_Frequency);
}

其中函数RCC_GetClocksFreq(&rcc_clocks)为将芯片内各模块的时钟频率保存在参数RCC_Clocks中，包含SYSCLK、HCLK、PCLKx、ADCCLK时钟频率值

void RCC_GetClocksFreq(RCC_ClocksTypeDef* RCC_Clocks)
{
……
}

typedef struct
{
  uint32_t SYSCLK_Frequency; //!<  SYSCLK clock frequency expressed in Hz 
  uint32_t HCLK_Frequency;   //!<  HCLK clock frequency expressed in Hz   
  uint32_t PCLK1_Frequency;  //!<  PCLK1 clock frequency expressed in Hz  
  uint32_t PCLK2_Frequency;  //!<  PCLK2 clock frequency expressed in Hz  
}RCC_ClocksTypeDef;

至此，完成获取HCLK频率HCLK_Frequencyfclk_freq = BSP_CPU_ClkFreq();

再继续深入：    CPU_TS_TmrFreqSet((CPU_TS_TMR_FREQ)fclk_freq);

#if (CPU_CFG_TS_TMR_EN == DEF_ENABLED)
void  CPU_TS_TmrFreqSet (CPU_TS_TMR_FREQ  freq_hz)
{
    CPU_TS_TmrFreq_Hz = freq_hz;
}
#endif

其中

typedef  unsigned  int         CPU_INT32U;    

#define  CPU_CORE_EXT  extern

typedef  CPU_INT32U  CPU_TS_TMR_FREQ;

CPU_CORE_EXT  CPU_TS_TMR_FREQ  CPU_TS_TmrFreq_Hz;

即：extern   unsigned  int   CPU_TS_TmrFreq_Hz；

也就是定义了一个全局变量，且该全局变量通过

fclk_freq = BSP_CPU_ClkFreq();//获取HCLK频率HCLK_Frequency

CPU_TS_TmrFreqSet((CPU_TS_TMR_FREQ)fclk_freq);

赋值为HCLK_Frequency；

至此 时间戳初始化完毕

下面该使用他了：

 //其中uint32_t TimeStart = 0,TimeEnd = 0 ,TimeUse = 0;是全局变量

TimeStart = OS_TS_GET();		
Delay_Ms( 20 );
TimeEnd = OS_TS_GET();
TimeUse = (TimeEnd - TimeStart) / ( 72000000 / 1000 );  单位为ms 

其中OS_TS_GET()为：

#if      OS_CFG_TS_EN == 1u
#define  OS_TS_GET()               (CPU_TS)CPU_TS_TmrRd()   /* See Note #2a.                                          */
#else
#define  OS_TS_GET()               (CPU_TS)0u
#endif

其中函数CPU_TS_TmrRd（）：

#define  CPU_REG_DEM_CR                       (*(CPU_REG32 *)0xE000EDFC)//使能DWT外设
#define  CPU_REG_DWT_CR                       (*(CPU_REG32 *)0xE0001000)//使能Cortex-M3 DWT CYCCNT寄存器 
#define  CPU_REG_DWT_CYCCNT                   (*(CPU_REG32 *)0xE0001004)//时间戳计数器变量向上计数
typedef  CPU_INT32U  CPU_TS_TMR;
#if (CPU_CFG_TS_TMR_EN == DEF_ENABLED)
CPU_TS_TMR  CPU_TS_TmrRd (void)
{
    CPU_TS_TMR  ts_tmr_cnts;


    ts_tmr_cnts = (CPU_TS_TMR)CPU_REG_DWT_CYCCNT;

    return (ts_tmr_cnts);
}
#endif

至此时间戳讲解完毕，写文章不易，记得一键三连