Timer Prescaler

RE: Timer Prescaler

Susheel Nuguru — Wed, 28 Oct 2015 20:24:19 GMT

I did not see anywhere that you have called the function nrf_drv_timer_enable. Without this the timer has been initialized but never actually started.

RE: Timer Prescaler

Lorens — Sun, 25 Oct 2015 12:34:28 GMT

I meant that that function didn't return(I just put a breakpoint at the following instruction, and it never stops). Now I solved setting the compare at 600, 1200, 1800, 2400, but this lead to another question, is there a lower bound for the compare? To check the interrupt frequency I toggle a pin every compare event, and even if I should have always the same interrupt distance (because of the equidistant comapare settings) the pin toggle is not always at the same interval (I am using an oscilloscope to check). Here's the function code: switch (event_type){

	case NRF_TIMER_EVENT_COMPARE0:
			Hw_Interface_SetOutput1();
	
	case NRF_TIMER_EVENT_COMPARE1:
				Hw_Interface_SetOutput();
				
	case NRF_TIMER_EVENT_COMPARE2:
		Hw_Interface_ResetOutput1();

	case NRF_TIMER_EVENT_COMPARE3:
			Hw_Interface_ResetOutput();
	}

Is there something wrong, or any limit I should follow? Thanks

RE: Timer Prescaler

Susheel Nuguru — Fri, 23 Oct 2015 10:31:28 GMT

LFCLK_XTAL should have nothing to do with TIMERs,

The define TIMER1_INSTANCE_INDEX is index to the timer driver member, so 0 is fine if Timer0 is not enabled.

Looking at the behaviour it seems that calling the function: SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, false); it has some problem. While not enabling the timer1 it works correctly

Can you please explain what "It has problems" mean?

RE: Timer Prescaler

Lorens — Fri, 23 Oct 2015 10:02:39 GMT

Looking at the behaviour it seems that calling the function: SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, false); it has some problem. While not enabling the timer1 it works correctly. The defines are the ones provided by Nordic SDK, the define #define TIMER1_INSTANCE_INDEX (TIMER0_ENABLED) is 0 because there is no TIMER0 enabled

If there are any other things you need to clarify the situation just ask.

Thanks

RE: Timer Prescaler

Susheel Nuguru — Thu, 22 Oct 2015 07:32:00 GMT

You code looks correct (except that i cannot see values of some defines) What is the symptoms you are seeing? is your handler not triggering correctly with softdevice? You description in the question was not so clear about the problem

RE: Timer Prescaler

Lorens — Wed, 21 Oct 2015 14:41:56 GMT

I use Timer1, for the reason you mentioned.

Here some parts of the Code:

#define TIMER1_ENABLED 1

#if (TIMER1_ENABLED == 1)
#define TIMER1_CONFIG_FREQUENCY    NRF_TIMER_FREQ_1MHz
#define TIMER1_CONFIG_MODE         TIMER_MODE_MODE_Timer
#define TIMER1_CONFIG_BIT_WIDTH    TIMER_BITMODE_BITMODE_16Bit
#define TIMER1_CONFIG_IRQ_PRIORITY APP_IRQ_PRIORITY_HIGH

#define TIMER1_INSTANCE_INDEX      (TIMER0_ENABLED)
#endif

Here the initialization:

    Timer_DRV.p_reg 			= NRF_TIMER1;
Timer_DRV.irq					= TIMER1_IRQn;
Timer_DRV.instance_id = TIMER1_INSTANCE_INDEX;

Timer_DRV_Conf.frequency					= TIMER1_CONFIG_FREQUENCY;
Timer_DRV_Conf.mode								= TIMER1_CONFIG_MODE;
Timer_DRV_Conf.bit_width					= TIMER1_CONFIG_BIT_WIDTH;
Timer_DRV_Conf.interrupt_priority	= TIMER1_CONFIG_IRQ_PRIORITY;
Timer_DRV_Conf.p_context					= timer_struct;

nrf_drv_timer_init(&Timer_DRV,
                          &Timer_DRV_Conf,
                          timer_clk_handler);

And then configuration interrupt:

            nrf_drv_timer_compare(&Timer_DRV, NRF_TIMER_CC_CHANNEL0, 60, true);
	nrf_drv_timer_compare(&Timer_DRV, NRF_TIMER_CC_CHANNEL1, 120, true);
	nrf_drv_timer_compare(&Timer_DRV, NRF_TIMER_CC_CHANNEL2, 180, true);
	nrf_drv_timer_extended_compare(&Timer_DRV, NRF_TIMER_CC_CHANNEL3, 240, NRF_TIMER_SHORT_COMPARE3_CLEAR_MASK,
                                    true);

Thank you

RE: Timer Prescaler

Lorens — Wed, 21 Oct 2015 14:39:17 GMT

Here there are a few character so I use an answer.

RE: Timer Prescaler

Susheel Nuguru — Wed, 21 Oct 2015 11:30:24 GMT

Which timer did you use , Timer0 or Timer1? Timer0 is restricted and is used by softdevice. Applications cannot use it (unless you are using Timeslot API)

can you put some code snippets for us to see what you are trying to do and what you want to achieve?