作者：付漢杰 hankf@amd.com

1. 硬件的Vivado Block design設計中，添加AXI Timer

2. 包含AXI Timer的頭文件

#include "xtmrctr.h"

3. 定義timer的參數和全局變量

/*
* The following constants map to the XPAR parameters created in the
* xparameters.h file. They are only defined here such that a user can easily
* change all the needed parameters in one place.
*/
#define TMRCTR_DEVICE_ID              XPAR_TMRCTR_0_DEVICE_ID


/*
 * This example only uses the 1st of the 2 timer counters contained in a
 * single timer counter hardware device
 */
#define TIMER_COUNTER_0   0


// #define XPAR_AXI_TIMER_0_CLOCK_FREQ_HZ 100000000U  100 000 000U
#define TMRCTR_DEVICE_FREQ_MS              (XPAR_TMRCTR_0_CLOCK_FREQ_HZ/1000)
#define TMRCTR_DEVICE_FREQ_US              (TMRCTR_DEVICE_FREQ_MS/1000)


#define TMRCTR_DEVICE_PERIOD_NS ( (1000*1000*1000)/XPAR_AXI_TIMER_0_CLOCK_FREQ_HZ )


XTmrCtrTimerCounter;/*TheinstanceoftheTmrctrDevice*/

4. 初始化AXI Timer

調用TmrCtrPolledInit()初始化AXI Timer, 也初始化了全局變量TimerCounter。

TmrCtrPolledInit(TMRCTR_DEVICE_ID,TIMER_COUNTER_0);

其中TmrCtrPolledInit()來自于xtmrctr_polled_example.c中的TmrCtrPolledExample()，可以在BSP中從AXI Timer的“Import Example”中導入。

5. 通過XTmrCtr_GetValue獲取時間戳

通過XTmrCtr_GetValue獲取時間戳，是以時鐘周期為單位的。可以轉化成微妙、毫秒、秒等單位。

    time_begin = XTmrCtr_GetValue(TmrCtrInstancePtr, TmrCtrNumber);
    for (i=0; i<100000; i++ ) {
        g_iLoopTest++;
    }
    time_end = XTmrCtr_GetValue(TmrCtrInstancePtr, TIMER_COUNTER_0);    


    if( time_end < time_begin ){
        time_diff = 0xffffffff - time_begin;
        time_diff = time_diff + time_end + 1;
    } else {
        time_diff = time_end - time_begin;
    }
    time_diff_us = time_diff/TMRCTR_DEVICE_FREQ_US;
    xil_printf("100K loop: %x : Timer diff: 0x%08x = %d Cycles, %d us, %d ms at %s : %d
",
????????????g_iLoopTest,?time_diff,?time_diff,?time_diff_us,?time_diff_us/1000,?__