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在弄segger的system view，CM3核可以直接用，挺好用。CM0的核要自己写一个返回时间戳的函数。
#if SEGGER_SYSVIEW_CORE == SEGGER_SYSVIEW_CORE_CM3
#define SEGGER_SYSVIEW_GET_TIMESTAMP() (*(U32 *)(0xE0001004)) // Retrieve a system timestamp. Cortex-M cycle counter.
#define SEGGER_SYSVIEW_TIMESTAMP_BITS 32 // Define number of valid bits low-order delivered by clock source
#else
#define SEGGER_SYSVIEW_GET_TIMESTAMP() SEGGER_SYSVIEW_X_GetTimestamp() // Retrieve a system timestamp via user-defined function
#define SEGGER_SYSVIEW_TIMESTAMP_BITS 32 // Define number of valid bits low-order delivered by SEGGER_SYSVIEW_X_GetTimestamp()
#endif
SEGGER_SYSVIEW_X_GetTimestamp这个函数要自己实现。
有embOS的实现如下：
/*********************************************************************
*
* SEGGER_SYSVIEW_X_GetTimestamp()
*
* Function description
* Returns the current timestamp in ticks using the system tick
* count and the SysTick counter.
* All parameters of the SysTick have to be known and are set via
* configuration defines on top of the file.
*
* Return value
* The current timestamp.
*
* Additional information
* SEGGER_SYSVIEW_X_GetTimestamp is always called when interrupts are
* disabled. Therefore locking here is not required.
*/
U32 SEGGER_SYSVIEW_X_GetTimestamp(void) {
U32 TickCount;
U32 Cycles;
U32 CyclesPerTick;
//
// Get the cycles of the current system tick.
// SysTick is down-counting, subtract the current value from the number of cycles per tick.
//
CyclesPerTick = SYST_RVR + 1;
Cycles = (CyclesPerTick - SYST_CVR);
//
// Get the system tick count.
//
TickCount = SEGGER_SYSVIEW_TickCnt;
//
// If a SysTick interrupt is pending, re-read timer and adjust result
//
if ((SCB_ICSR & SCB_ICSR_PENDSTSET_MASK) != 0) {
Cycles = (CyclesPerTick - SYST_CVR);
TickCount++;
}
Cycles += TickCount * CyclesPerTick;
return Cycles;
}
无OS的
/*********************************************************************
*
* SEGGER_SYSVIEW_X_GetTimestamp()
*
* Function description
* Returns the current timestamp in ticks using the system tick
* count and the SysTick counter.
* All parameters of the SysTick have to be known and are set via
* configuration defines on top of the file.
*
* Return value
* The current timestamp.
*
* Additional information
* SEGGER_SYSVIEW_X_GetTimestamp is always called when interrupts are
* disabled.
* Therefore locking here is not required and OS_GetTime_Cycles() may
* be called.
*/
U32 SEGGER_SYSVIEW_X_GetTimestamp(void) {
U32 Time;
U32 Cnt;
Time = SEGGER_SYSVIEW_TickCnt;
Cnt = CMT0_CMCNT;
//
// Check if timer interrupt pending ...
//
if ((*(volatile U8*)(IRR_BASE_ADDR + OS_TIMER_VECT) & (1u << 0u)) != 0u) {
Cnt = CMT0_CMCNT; // Interrupt pending, re-read timer and adjust result
Time++;
}
return ((SYSVIEW_TIMESTAMP_FREQ/1000) * Time) + Cnt;
}
怎么写freeRTOS的？
或者给个思路？
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发表于 2017-3-31 12:57:14
楼主
