RTC every second generates TIMER COUNT through PPI

[Chocol8]

Hello,

This case is a part of a private case. Unfortunately Jørgen havent responded for few days. I believe he has days off or something, therefore I am willing to receive help in a public case because of an upcoming deadline.

My setup is pca10040 board, s132, sdk14.2. ble_app_uart example augmented with rtc and pii examples.

My goal is to track real time using lowest possibile energy consumptions while keeping time as precise as possibile. In code I want to increase RTC2 value every second. This generates an event every second and through PPI triggers TIMER COUNT task. I want to read this task and convert it to seconds:minutes:hours:days.

I have read many posts talking about this, unfortunately I am unable to solve this by myself. These are the initializations I use at the moment:

static const nrf_drv_rtc_t rtc2_instance = NRF_DRV_RTC_INSTANCE(2); /**< Declaring an instance of nrf_drv_rtc for RTC. */
static const nrf_drv_timer_t m_timer0 = NRF_DRV_TIMER_INSTANCE(2);
static nrf_ppi_channel_t m_ppi_channel3;

static void timer0_event_handler(nrf_timer_event_t event_type, void * p_context)
{
}

static void ppi_init(void)
{
    uint32_t err_code = NRF_SUCCESS;

    err_code = nrf_drv_ppi_init();
    APP_ERROR_CHECK(err_code);

    err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel3);
    APP_ERROR_CHECK(err_code);
    
    uint32_t timer_count_count_task_addr    = nrf_drv_timer_task_address_get(&m_timer0, NRF_TIMER_TASK_COUNT);
    
    err_code = nrf_drv_ppi_channel_assign(m_ppi_channel3,
                                          nrf_drv_rtc_event_address_get(&rtc2_instance, NRF_RTC_EVENT_COMPARE_0),
                                          nrf_drv_timer_task_address_get(&m_timer0, NRF_TIMER_TASK_COUNT));
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_drv_ppi_channel_fork_assign(m_ppi_channel3,
                                          nrf_drv_rtc_task_address_get(&rtc2_instance, NRF_RTC_TASK_CLEAR));
    APP_ERROR_CHECK(err_code);
    
    // Enable both configured PPI channels
    err_code = nrf_drv_ppi_channel_enable(m_ppi_channel3);
    APP_ERROR_CHECK(err_code);
}

static void timer0_init(void)
{
    // Check TIMER0 configuration for details.
    nrf_drv_timer_config_t timer_cfg = NRF_DRV_TIMER_DEFAULT_CONFIG;
    timer_cfg.mode =NRF_TIMER_MODE_LOW_POWER_COUNTER;
    ret_code_t err_code = nrf_drv_timer_init(&m_timer0, &timer_cfg, timer0_event_handler);
    APP_ERROR_CHECK(err_code);

    nrf_drv_timer_compare(&m_timer0,
                      NRF_TIMER_CC_CHANNEL0,
                      1, // after one second compare happens
                      true);
}

static void rtc_handler_empty(nrf_drv_rtc_int_type_t int_type)
{

}

static void rtc_config(void)
{
    uint32_t err_code;

    //Initialize RTC instance
    nrf_drv_rtc_config_t config = NRF_DRV_RTC_DEFAULT_CONFIG;
    config.prescaler = 4095;
    err_code = nrf_drv_rtc_init(&rtc2_instance, &config, rtc_handler_empty);
    APP_ERROR_CHECK(err_code);

    //nrf_drv_rtc_tick_enable(&rtc2_instance,true);
    err_code = nrf_drv_rtc_cc_set(&rtc2_instance,0,8,false); // 32768/4096 gives 8 ticks per second.
    APP_ERROR_CHECK(err_code);
	//Power on RTC instance
    nrf_drv_rtc_enable(&rtc2_instance);
}

What I perceive is that RTC is ticking every second, however TIMER is not changing. I do not know where exactly to look for TIMER COUNT value. I have tried to capture values like this:

NRF_TIMER2->TASKS_CAPTURE[2] = 1;  // This is asking to capture the current counter into CC[2]
TIMER_COUNTER = NRF_TIMER1->CC[2];   // counter value  at the instant when capture task was triggered is now ready to be read in CC[2]

by putting these lines in main function while(1) loop and in timer0_event_handler, nevertheless this did not worked out.

Please, pin point where I am making mistake here, where should look for increasing TIMER COUNT value and how to make it increase every second. Thank you.