Timer interrupt handler not getting called, please help

[Insaf]

I have enabled Timer 2 with 31250Hz frequency. I wanted to call an interrupt after 10ms, ie 312 ticks for the timer. But the interrupt is not getting called, I have spent some time finding the problem, but couldn't find.

Please check the following code, and help me to fix it.

#define UART_TX_BUF_SIZE 256                                                          /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 1                                                            /**< UART RX buffer size. */

const nrf_drv_timer_t decode_timeout_timer = NRF_DRV_TIMER_INSTANCE(2); //Time out timer, used to stop decoding
static bool			m_timer_on;
static uint32_t m_tsop_pin;
static uint32_t err_code = NRF_SUCCESS;
static uint16_t m_array_index;

static void decode_timeout_timer_event_handler(nrf_timer_event_t event_type, void * p_context)
{    
	printf("decode timeout event handler got called\n");
    if(event_type == NRF_TIMER_EVENT_COMPARE0)
    {
			printf("TIMEOUT\n");
			nrf_drv_timer_pause(&decode_timeout_timer);
    }    
}

void tsop_pin_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
	printf("\nTimer value is: timer2 %u\n", nrf_drv_timer_capture(&decode_timeout_timer, NRF_TIMER_CC_CHANNEL0));
	if(pin == m_tsop_pin && action == NRF_GPIOTE_POLARITY_TOGGLE )
	{
		if(!m_timer_on)
		{
			printf("Starting decoding...\n");
			m_timer_on = true;
			nrf_drv_timer_enable(&decode_timeout_timer);
		}
	}
}

static void gpiote_init()
{
	if(!nrf_drv_gpiote_is_init())
	{
    err_code = nrf_drv_gpiote_init();
	}
	
	nrf_drv_gpiote_in_config_t config = GPIOTE_CONFIG_IN_SENSE_TOGGLE(true);
	config.pull = NRF_GPIO_PIN_PULLUP;
	
	err_code =  nrf_drv_gpiote_in_init(m_tsop_pin, &config, tsop_pin_handler);
	nrf_drv_gpiote_in_event_enable(m_tsop_pin, true);

}

static void decode_timeout_timer_init()
{
	nrf_drv_timer_config_t timer_config =  {
        .frequency          = NRF_TIMER_FREQ_31250Hz,
        .mode               = NRF_TIMER_MODE_TIMER,
        .bit_width          = NRF_TIMER_BIT_WIDTH_16,
        .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
        .p_context          = (void *)(uint32_t) decode_timeout_timer.instance_id
    };
	
	err_code |= nrf_drv_timer_init(&decode_timeout_timer, &timer_config, decode_timeout_timer_event_handler);
	
	uint32_t time_out_ms = 10;
  uint32_t time_ticks;
	time_ticks = nrf_drv_timer_ms_to_ticks(&decode_timeout_timer, time_out_ms);
	printf("time_ticks: %u", time_ticks);
	//nrf_drv_timer_compare_int_enable(&decode_timeout_timer, NRF_TIMER_CC_CHANNEL0);
  nrf_drv_timer_compare(&decode_timeout_timer, NRF_TIMER_CC_CHANNEL0, time_ticks, true);
	 
}

void uart_error_handle(app_uart_evt_t * p_event)
{
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_communication);
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_code);
    }
}

/**
 * @brief Function for application main entry.
 */
int main(void)
{

    uint32_t err_code;
    const app_uart_comm_params_t comm_params =
     {
         RX_PIN_NUMBER,
         TX_PIN_NUMBER,
         RTS_PIN_NUMBER,
         CTS_PIN_NUMBER,
         APP_UART_FLOW_CONTROL_ENABLED,
         false,
         UART_BAUDRATE_BAUDRATE_Baud38400
     };

    APP_UART_FIFO_INIT(&comm_params,
                    UART_RX_BUF_SIZE,
                    UART_TX_BUF_SIZE,
                    uart_error_handle,
                    APP_IRQ_PRIORITY_LOW,
                    err_code);

    APP_ERROR_CHECK(err_code);
		 
		 m_tsop_pin = 4;
		 decode_timeout_timer_init();
		gpiote_init();
		 
    while (true)
    {
        // Do Nothing - GPIO can be toggled without software intervention.
    }
}


/** @} */

[RK]

Don't see anywhere you start a low frequency clock in that code. And please don't just busy spin at the end, at least put a _WFE in it.

[Insaf]

Thanks for replying, I have started the timer in the gpio pin handler( tsop_pin_handler function). Timer is working fine, I can capture the timer values. Also, the interrupt handler gets called when the timer values gets reset to 0 after reaching 16 bit limit.

Okay, I will put _WFE in the main loop. But this program is for testing purpose, that's why I didnt put that.

[Insaf]

I found the problem. The interrupt is not getting called because, I am also capturing the timer values from the same channel(CC_CHANNEL0). So when I changed the interrupt listen channel to CC_CHANNEL1, everything works fine. I can capture the values from CHANNEL0, and also I can listen for EVENT_COMPARE interrupt at CHANNEL1.

What I learnt is, don't capture and listen to the same timer channel. Please correct me, if I am wrong.

[RK]

well you can do what you want but yes the capture captures into the same register you use for timeout which means you'll never time out. Good that you found your error. Nice debugging.