Timers in nRF9160 SOC

RE: Timers in nRF9160 SOC

Didrik Rokhaug — Fri, 24 Apr 2020 09:06:38 GMT

[quote user="hng"]16bits counter can count to 65535 x32us = 2,09712‬ s, is it correct?[/quote]

Yes, that is correct.

cc_value is the number of ticks you count up to. You can get this value by multiplying the TIMEOUT with the frequency (assuming you are working with s and Hz as units, if not apply correct scaling).

You can find the calculations done in nrfx_timer_ms_to_ticks here: https://github.com/zephyrproject-rtos/hal_nordic/blob/master/nrfx/hal/nrf_timer.h#L715

RE: Timers in nRF9160 SOC

Hoang — Thu, 23 Apr 2020 20:26:08 GMT

Dear Didrik Rokhaug,

the counter 16bits, xFFFF = 65 535 max value and with the

my_timer_config.frequency = NRF_TIMER_FREQ_31250Hz;

--> T = 32us

16bits counter can count to 65535 x32us = 2,09712‬ s, is it correct?

I checked on the document:

void nrfx_timer_compare	(	nrfx_timer_t const *const	p_instance,
		nrf_timer_cc_channel_t	cc_channel,
		uint32_t	cc_value,
		bool	enable_int
	)

cc_value is the ticks/ms, is it right ? how can we calculate this value from the TIMEOUT (as nrfx_timer_ms_to_ticks(&my_timer, TIMEOUT);)

Thanks so much

Regards,

Hoang Nguyen

RE: Timers in nRF9160 SOC

Didrik Rokhaug — Thu, 23 Apr 2020 13:43:33 GMT

Hi Hoang.

The counter only has 16 bits, so it is not able to count up to 300000 * ticks/ms.

However, I am not sure if I would use a timer for that in the first place. Instead, I would take a look delayed work items: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.2.0/zephyr/reference/kernel/threads/workqueue.html#delayed-work

Best regards,

Didrik

RE: Timers in nRF9160 SOC

Hoang — Thu, 23 Apr 2020 11:35:34 GMT

Hi Didrik Rokhaug

How can I create a timer, with the timeout is 5mn, after 5mn, it will enable GPS - THINGY:91?

In your code, I changed the TIMEOUT = 300000 // 5mn, but the interrupt always happened every second.

Thanks,

Hoang

RE: Timers in nRF9160 SOC

praveenpalaparthi — Wed, 08 Apr 2020 11:45:23 GMT

Hi Didrik,

Thank you for sharing me sample code.

regards,

Praveen

RE: Timers in nRF9160 SOC

Didrik Rokhaug — Wed, 08 Apr 2020 10:57:29 GMT

Hi.

First, you might also want to take a look at Zephyr's timer API, even though these are software timers: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/reference/kernel/timing/timers.html

Other than that, I do not know about any other Zephyr API that access to timers. However, you can still use the nrfx drivers from the nRF5 SDK.

You can find the available API in <NCS>/modules/hal/nordic/nrfx/drivers/include/nrfx_timer.h.

Attached is a quick sample application that sets up an interrupt to happen every second.

Best regards,

Didrik

devzone.nordicsemi.com/.../timer.zip