55 lines
1.3 KiB
Markdown
55 lines
1.3 KiB
Markdown
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# bsp_dwt
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DWT是stm32内部的一个"隐藏资源",他的用途是给下载器提供准确的定时,从而为调试信息加上时间戳.并在固定的时间间隔将调试数据发送到你的xxlink上.
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## 常用功能
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### 计算两次进入同一个函数的时间间隔
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```c
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static uint32_t cnt;
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float deltaT;
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deltaT=DWT_GetDeltaT(&cnt);
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```
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### 计算执行某部分代码的耗时
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```c
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float start,end;
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start=DWT_DetTimeline_ms();
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// some proc to go...
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for(uint8_t i=0;i<10;i++)
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foo();
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end = DWT_DetTimeline_ms()-start;
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```
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我们还提供了一个宏用于调试计时:
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```c
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#define TIME_ELAPSE(dt, code) \
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do \
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{ \
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float tstart = DWT_GetTimeline_s(); \
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code; \
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dt = DWT_GetTimeline_s() - tstart; \
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LOGINFO("[DWT] " #dt " = %f s\r\n", dt); \
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} while (0)
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```
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传入一个float类型的变量,并将你要执行的代码写入第二个参数:
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```c
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static float my_func_dt;
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TIME_ELAPSE(my_func_dt,
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Function1(vara);
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Function2(some, var);
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Function3(your,param);
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// something more
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);
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// my_func_dt can be used for other purpose then;
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```
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