TM4C123的systick时钟如何使用。

yifei wang2

我想使用TM4C123的滴答时钟系统，但是发现找到的systick时钟的相关函数，但是我不知道计数值的对应关系

#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickValueGet \
((uint32_t (*)(void))ROM_SYSTICKTABLE[0])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickEnable \
((void (*)(void))ROM_SYSTICKTABLE[1])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickDisable \
((void (*)(void))ROM_SYSTICKTABLE[2])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickIntEnable \
((void (*)(void))ROM_SYSTICKTABLE[3])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickIntDisable \
((void (*)(void))ROM_SYSTICKTABLE[4])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickPeriodSet \
((void (*)(uint32_t ui32Period))ROM_SYSTICKTABLE[5])
#endif
#if defined(TARGET_IS_TM4C123_RA1) || \
defined(TARGET_IS_TM4C123_RA3) || \
defined(TARGET_IS_TM4C123_RB1) || \
defined(TARGET_IS_TM4C129_RA0) || \
defined(TARGET_IS_TM4C129_RA1)
#define ROM_SysTickPeriodGet \
((uint32_t (*)(void))ROM_SYSTICKTABLE[6])
#endif

例如，装载值对应的是多长时间

9 年多前

0 xyz549040622 9 年多前

Guru 65885 points

SysTickPeriodSet用这个函数进行设置了。

Sets the period of the SysTick counter.
Prototype:
void
SysTickPeriodSet(uint32_t ui32Period)
Parameters:
ui32Period is the number of clock ticks in each period of the SysTick counter and must be
between 1 and 16, 777, 216, inclusive.
Description:
This function sets the rate at which the SysTick counter wraps, which equates to the number
of processor clocks between interrupts.
Note:
Calling this function does not cause the SysTick counter to reload immediately. If an immediate
reload is required, the NVIC_ST_CURRENT register must be written. Any write to this register
clears the SysTick counter to 0 and causes a reload with the ui32Period supplied here on the
next clock after SysTick is enabled.
Returns:
None.