Hi,
I'd like to get a timer with 1ms interval or higher resolution, and found some questions about this:
-
If the app_timer is used, looks like we only can get minimum interval 5ms. With the less interval, it causes the system crashed and reboot. BTW, to use the 5ms interval, I updated the example macro MS_TO_TICK to below:
#define MS_TO_TICK(MS) ((TICKS_PER_100MS * MS) / 100)
Is 5ms as the resolution for app_timer expected? If it's using 32K RTC as the clock source, I suppose the resolution should be much higher, right?
- I turned to solution with the timer in TIMER mode as the example suggested, but observed some confusing issues:
For easier usage, I referred the code of app_timer to define below macros:
#define ROUNDED_DIV(A, B) (((A) + ((B) / 2)) / (B))
#define TIMER_PRESCALER 6
#define TIMER_FREQUENCY (256 * 1024) /* 16M / exp(2, PRESCALER) */
#define TIMER_TICKS_PER_MS ROUNDED_DIV(TIMER_FREQUENCY, 1000)
#define TIMER_MS_TO_TICK(MS) (TIMER_TICKS_PER_MS * MS)
and set CC as below:
NRF_TIMER2->CC[0] = TIMER_MS_TO_TICK(100);
But from the logs I added in timer handler, this setting gets 25ms interval instead of 100ms. What am I missing for this setting?
Another issue about timer is that whatever I set for BITMODE, 16 bit or 32 bit, the max CC value is always (64K - 1). If this is true, it will limit the max interval I'm trying to set. Could you please confirm this?
Thanks & Regards, Stanley
