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[update] 获取timer count时，防止因中断到来导致overflow更新

This commit is contained in:
luanxueguang 2020-11-21 17:44:52 +08:00
parent 9dc0bbb814
commit accb73d8df
1 changed files with 8 additions and 1 deletions
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9
components/drivers/hwtimer/hwtimer.c
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@ -10,6 +10,7 @@
#include <rtthread.h>
#include <rtdevice.h>
#include <rthw.h>
rt_inline rt_uint32_t timeout_calc(rt_hwtimer_t *timer, rt_hwtimerval_t *tv)
{
@ -144,19 +145,25 @@ static rt_size_t rt_hwtimer_read(struct rt_device *dev, rt_off_t pos, void *buff
rt_hwtimer_t *timer;
rt_hwtimerval_t tv;
rt_uint32_t cnt;
rt_base_t level;
rt_int32_t overflow;
float t;
timer = (rt_hwtimer_t *)dev;
if (timer->ops->count_get == RT_NULL)
return 0;
level = rt_hw_interrupt_disable();
cnt = timer->ops->count_get(timer);
overflow = timer->overflow;
rt_hw_interrupt_enable(level);
if (timer->info->cntmode == HWTIMER_CNTMODE_DW)
{
cnt = (timer->freq * timer->period_sec) - cnt;
}
t = timer->overflow * timer->period_sec + cnt/(float)timer->freq;
t = overflow * timer->period_sec + cnt/(float)timer->freq;
tv.sec = t;
tv.usec = (t - tv.sec) * 1000000;
size = size > sizeof(tv)? sizeof(tv) : size;