In Nrf5 sdk V15 their is a micro
ticks = APP_TIMER_TICKS(MS);
My question is what is the maximum value of ms which can be used as input.
the same question goes to the function
app_timer_start()
Please assist
In Nrf5 sdk V15 their is a micro
ticks = APP_TIMER_TICKS(MS);
My question is what is the maximum value of ms which can be used as input.
the same question goes to the function
app_timer_start()
Please assist
Hi, this ticket and this ticket both answer your question.
The RTC features a 24 bit counter and a 12 bit prescaler, so the maximum value will be
(2*24) * (APP_TIMER_CONFIG_RTC_FREQUENCY + 1) * 1000 / APP_TIMER_CLOCK_FREQ
depending on how you configure the RTC prescaler value (APP_TIMER_CONFIG_RTC_FREQUENCY).
The clock frequency of the RTC timer (APP_TIMER_CLOCK_FREQ) is 32768 (32 kHz).
So for example with a prescaler value of 15, the RTC will overflow after 8 192 000 ms, which will is in turn the maximum value of MS you can use as input to APP_TIMER_TICKS(MS).
(2^24) * (15 + 1) * 1000 / 32768 = 8 192 000ms = ~136,5 minutes.
This will then give you a period (or counter resolution) of
8 192 000 / 16 777 216 = ~488 us
The image below is taken from the product specification of the nRF52832 (and similar ones can be found for the other chips). So for example with a prescaler of 0 and counter resolution of 30.517 microseconds, the maximum value of MS is 512 000 milliseconds.
Best regards,
Heidi
Hi, this ticket and this ticket both answer your question.
The RTC features a 24 bit counter and a 12 bit prescaler, so the maximum value will be
(2*24) * (APP_TIMER_CONFIG_RTC_FREQUENCY + 1) * 1000 / APP_TIMER_CLOCK_FREQ
depending on how you configure the RTC prescaler value (APP_TIMER_CONFIG_RTC_FREQUENCY).
The clock frequency of the RTC timer (APP_TIMER_CLOCK_FREQ) is 32768 (32 kHz).
So for example with a prescaler value of 15, the RTC will overflow after 8 192 000 ms, which will is in turn the maximum value of MS you can use as input to APP_TIMER_TICKS(MS).
(2^24) * (15 + 1) * 1000 / 32768 = 8 192 000ms = ~136,5 minutes.
This will then give you a period (or counter resolution) of
8 192 000 / 16 777 216 = ~488 us
The image below is taken from the product specification of the nRF52832 (and similar ones can be found for the other chips). So for example with a prescaler of 0 and counter resolution of 30.517 microseconds, the maximum value of MS is 512 000 milliseconds.
Best regards,
Heidi