nrfx timer multiple compare interrupts enabled

[SRall]

NCS 2.9.1 - NRF5340DK

I am trying to use multiple compare channels on Timer1 (output_timer) such that an interrupt handler fires for both compare values, the second of which is enabled with the compare_extend shortcut such that it clears the timer. My app_timer_init function also inits Timer0 (timer_inst). 

static void output_timer_handler(nrf_timer_event_t event_type, void * p_context)
{
    switch(event_type)
    {
        case NRF_TIMER_EVENT_COMPARE1://3 or 1us - timer doesn't stop
            //Drive data pin low
            NRF_P1->OUTCLR  = (1UL << (POLL_PIN - 32));

            break;
        case NRF_TIMER_EVENT_COMPARE0://4us - timer clears
            // Set the next compare value on CC1
            // Drive data pin high
            NRF_P1->OUTSET  = (1UL << (POLL_PIN - 32));

            break;
        default: 
            break;
    }
}

static void app_timer_init()
{
    nrfx_err_t status;
    (void)status;

    
    uint32_t base_frequency = NRF_TIMER_BASE_FREQUENCY_16MHZ;
    nrfx_timer_config_t timer_config = NRFX_TIMER_DEFAULT_CONFIG(base_frequency);
    timer_config.bit_width = NRF_TIMER_BIT_WIDTH_32;
    timer_config.p_context = "Some context";

    nrfx_timer_config_t timer_config2 = NRFX_TIMER_DEFAULT_CONFIG(base_frequency);
    timer_config2.bit_width = NRF_TIMER_BIT_WIDTH_32;

    status = nrfx_timer_init(&timer_inst, &timer_config, NULL);
    if(status != NRFX_SUCCESS)
    {
        printk("Error Timer Init No: %d\n", status);
        return;
    }
    else
        printk("Controller Response Timer Initialized\n");

    nrfx_timer_clear(&timer_inst);

    status = nrfx_timer_init(&output_timer, &timer_config2, output_timer_handler);
    if(status != NRFX_SUCCESS)
    {
        printk("Error Timer Init No: %d\n", status);
        return;
    }
    else
        printk("Poll Timer Initialized\n");

    uint32_t period_len = nrfx_timer_us_to_ticks(&output_timer, (uint32_t) 4);
    uint32_t zero_interval = nrfx_timer_us_to_ticks(&output_timer, (uint32_t) 1);

    nrfx_timer_extended_compare(&output_timer, NRF_TIMER_CC_CHANNEL0, period_len, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);
    nrfx_timer_compare(&output_timer, NRF_TIMER_CC_CHANNEL1, zero_interval, true);
                                                        //                    ^ enabling this iterrupt causes no output
    
    nrfx_timer_clear(&output_timer);

}

This is how I've connected IRQ in main().

IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_TIMER_INST_GET(TIMER_INST_IDX)), IRQ_PRIO_LOWEST,
                    NRFX_TIMER_INST_HANDLER_GET(TIMER_INST_IDX), 0, 0);

IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_TIMER_INST_GET(OUTPUT_TIMER_IDX)), IRQ_PRIO_LOWEST,
                    NRFX_TIMER_INST_HANDLER_GET(OUTPUT_TIMER_IDX), 0, 0);

The problem arises when I enable just the second compare interrupt on the output_timer. The application compiles but does not output anything to the console. When I set the int_enable parameter in the nrfx_timer_compare() function to false, everything behaves as expected. 

Am I implementing this incorrectly?

[Sigurd Hellesvik]

Hi Sam,

Do you do anything else in the code when you try this, or only the timer stuff?

Regards,
Sigurd Hellesvik

[SRall]

I have gppi channels setup (but not in use when testing this) and that's it. Eventually I will be adding Bluetooth, but I don't have that code included when testing this. 

[Sigurd Hellesvik]

The application compiles but does not output anything to the console.

So not even the introductory prints? Seems odd if nothing happens before the line that seems to cause the error.

Try to enable CONFIG_LOG, so that eventual faults get logged.

Try to debug your application and place a breakpoint inside the IRQ function. Perhaps something happens so that the IRQ triggers all the time, stopping other things from running?

[SRall]

After more troubleshooting I found that my intervals were too short for anything to be able to print before the timer events likely crashed the application. It only works on a minimum value of 8ish microseconds. I am trying to implement it another way with gppi channels but am getting stuck for a different reason it seems. I made another ticket about it here.