how can i make system tick funtion?

RE: how can i make system tick funtion?

Ole Morten — Wed, 21 Aug 2013 09:21:06 GMT

I'm sorry, but I still have serious problems understanding what you want. If you want a TICK with a frequency of 32.768 kHz, you should just use the RTC. You will not get a precise 32.768 kHz tick by using the 16 MHz timers. If you want a tick for every 1 ms, you have to use one of the 16 MHz timers, and do as I said in this initial answer.

RE: how can i make system tick funtion?

Guest — Mon, 19 Aug 2013 10:51:54 GMT

@Ole I'm sorry for making a confusion to you. I made code like to below for using 16Mhz system clock.

/* Start 16 MHz crystal oscillator */ NRF_CLOCK->EVENTS_HFCLKSTARTED = 0; NRF_CLOCK->TASKS_HFCLKSTART = 1;

/* Wait for the external oscillator to start up */
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)		
{
}
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

after this routine, I would like to configure 1ms tick timer. I think that the 1ms tick timer seem to be made using timer interrupt(timerX_IRQn). So, Can I make the tick timer using 32.768Hz with system clock 16MHz? If this is possible, How can I make code?

I look forward to wait for your detailed guide.

RE: how can i make system tick funtion?

Bastiaan — Mon, 19 Aug 2013 10:51:54 GMT

@Ole I'm sorry for making a confusion to you. I made code like to below for using 16Mhz system clock.

/* Start 16 MHz crystal oscillator */ NRF_CLOCK->EVENTS_HFCLKSTARTED = 0; NRF_CLOCK->TASKS_HFCLKSTART = 1;

/* Wait for the external oscillator to start up */
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)		
{
}
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;

I look forward to wait for your detailed guide.

RE: how can i make system tick funtion?

Ole Morten — Mon, 19 Aug 2013 07:21:07 GMT

I'm not quite sure I understand your question correctly, but no matter what clock source you use, the MCU will run on 16 MHz. Could you perhaps explain a little more if you have further questions?

RE: how can i make system tick funtion?

Bastiaan — Sat, 17 Aug 2013 13:34:45 GMT

@Ole As you are comment, I have to 16Mhz osc for accurate 1ms tick. currently, my system is using a system clock 16MHz. For using RTC1, Is the system clock set 32.768KHz?

RE: how can i make system tick funtion?

Guest — Sat, 17 Aug 2013 13:34:45 GMT

@Ole As you are comment, I have to 16Mhz osc for accurate 1ms tick. currently, my system is using a system clock 16MHz. For using RTC1, Is the system clock set 32.768KHz?

RE: how can i make system tick funtion?

Bastiaan — Sat, 17 Aug 2013 13:23:59 GMT

@philip, Thank you for your help. that's work it.

RE: how can i make system tick funtion?

Guest — Sat, 17 Aug 2013 13:23:59 GMT

@philip, Thank you for your help. that's work it.

RE: how can i make system tick funtion?

Philip Freidin — Sat, 17 Aug 2013 01:49:21 GMT

Those #defines are in nrf51_bitfields.h

RE: how can i make system tick funtion?

Bastiaan — Fri, 16 Aug 2013 21:38:49 GMT

@philips, where can I find the below variables? CLOCK_LFCLKSRC_SRC_RC, CLOCK_LFCLKSRC_SRC_Pos, RTC_EVTENSET_TICK_Enabled, RTC_EVTENSET_TICK_Pos, RTC_INTENSET_TICK_Enabled and RTC_INTENSET_TICK_Pos.

RE: how can i make system tick funtion?

Guest — Fri, 16 Aug 2013 21:38:49 GMT

@philips, where can I find the below variables? CLOCK_LFCLKSRC_SRC_RC, CLOCK_LFCLKSRC_SRC_Pos, RTC_EVTENSET_TICK_Enabled, RTC_EVTENSET_TICK_Pos, RTC_INTENSET_TICK_Enabled and RTC_INTENSET_TICK_Pos.

RE: how can i make system tick funtion?

Philip Freidin — Fri, 16 Aug 2013 11:13:56 GMT

Do not replace nrf51.h , you need it.

Replace the #include "nrf51_PF_Lib.h" with this:

extern uint32_t RTC1_Milliseconds; extern uint32_t RTC1_Seconds;

RE: how can i make system tick funtion?

Bastiaan — Fri, 16 Aug 2013 10:22:29 GMT

@Philip As you inform to me, I saw RTC1_ms_timer.c registering on thread that you link. but, I don't have head file, nRF51_PF_Lib.h. Is this header same as nrf51.h file?

Altough I replace nrf51_PF_Lib.h to nrf51.h, the compiler don't find follow define variables : CLOCK_LFCLKSRC_SRC_RC, CLOCK_LFCLKSRC_SRC_Pos, RTC_EVTENSET_TICK_Enabled, RTC_EVTENSET_TICK_Pos, RTC_INTENSET_TICK_Enabled and RTC_INTENSET_TICK_Pos.

Where can these be finded?

RE: how can i make system tick funtion?

Guest — Fri, 16 Aug 2013 10:22:29 GMT

@Philip As you inform to me, I saw RTC1_ms_timer.c registering on thread that you link. but, I don't have head file, nRF51_PF_Lib.h. Is this header same as nrf51.h file?

Where can these be finded?

RE: how can i make system tick funtion?

Ole Morten — Tue, 06 Aug 2013 04:32:45 GMT

Remember that a 16 MHz crystal is required for radio operation. However, timers can also run on the internal 16 MHz RC oscillator.

I'd also be happy if you could accept one of the answers, to clear up the discussion. :-)

RE: how can i make system tick funtion?

Guest — Mon, 05 Aug 2013 21:01:24 GMT

Thank you for your code. I will check the code.

RE: how can i make system tick funtion?

Bastiaan — Mon, 05 Aug 2013 21:01:24 GMT

Thank you for your code. I will check the code.

RE: how can i make system tick funtion?

Bastiaan — Mon, 05 Aug 2013 20:58:16 GMT

Thank you for your detailed explanation. I will check whether there is 16Mhz crystal in my module. If there is it, I will try your comment.

RE: how can i make system tick funtion?

Guest — Mon, 05 Aug 2013 20:58:16 GMT

Thank you for your detailed explanation. I will check whether there is 16Mhz crystal in my module. If there is it, I will try your comment.

RE: how can i make system tick funtion?

Ole Morten — Mon, 05 Aug 2013 05:50:02 GMT

If you need exactly 1 ms ticks, you will have to use the 16 MHz timers, since the low-frequency clock is 32.768 kHz (32768 Hz), giving ticks with a frequency of 32768/(32+1) = 992.96... Hz.

The 16 MHz timers does not have a TICK interrupt, so to use them for such purpose, I'd recommend to set the PRESCALER register to something appropriate, set one of the CC values correctly and enable the COMPAREX_CLEAR shortcut, so that the timer restarts on each compare. After this, you can enable the COMPAREX interrupt in INTEN and the TIMERX interrupt in the NVIC, and then just start the TIMER and let it run.

For completeness, making a tick is easier with the RTC; you just set the PRESCALER correctly, enable the TICK interrupt in INTEN and the RTC interrupt in the NVIC and then start the RTC. Remember to start the LFCLK before starting the RTC.

RE: how can i make system tick funtion?

Philip Freidin — Sun, 04 Aug 2013 16:02:05 GMT

I have posted some code in my answer to this thread. It implements a 1 ms tick using RTC1. Maybe this will meet your needs.

**[comprehension-question-timer](devzone.nordicsemi.com/.../comprehension-question-timer)**