Zephyr nrfx_timer_compare

Hi Bob

There is no reason why CC5 shouldn't work. 

One thing I notice in your code is that you refer to your own event handler in the call to IRQ_DIRECT_CONNECT, rather than the interrupt handler of the nrfx_timer library. 

Could you change this to point to the nrfx handler instead, like shown here, and see if it works better?

Best regards
Torbjørn

Hi Torbjørn,

Thanks for the reply.

I changed it into:

{
    IRQ_DIRECT_CONNECT(TIMER4_IRQn, IRQ_PRIO_LOWEST, bus_timer_event, 0);
    
    const nrfx_timer_config_t bus_timer_config =
        {
            .frequency          = NRF_TIMER_FREQ_1MHz,
            .mode               = NRF_TIMER_MODE_TIMER,
            .bit_width          = NRF_TIMER_BIT_WIDTH_32,
            .interrupt_priority = 3,
            .p_context          = NULL
        } ;


    nrfx_timer_init( &bus_timer, &bus_timer_config, bus_timer_event );
    
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL0, _measdelay, true );  
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL1, _measdelay+417, true );
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL2, 2400, true );          
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL3, 5500, true );          
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL4, 13500, true );         
    nrfx_timer_compare( &bus_timer, NRF_TIMER_CC_CHANNEL5, 16300, true );         
        
    nrfx_ppi_channel_alloc( &ppi_channel );
    nrfx_timer_enable( &bus_timer );
}

void bus_timer_event(nrf_timer_event_t event_type, void * p_context)
{
    switch( event_type )
    {
    case NRF_TIMER_EVENT_COMPARE0 : 
        ...
        break;
    case NRF_TIMER_EVENT_COMPARE1 : 
        ...
        break;
    case NRF_TIMER_EVENT_COMPARE2 : 
        ...
        break;
    case NRF_TIMER_EVENT_COMPARE3 : 
        ...
        break; 
    case NRF_TIMER_EVENT_COMPARE4 : 
        ...
        break;    
    case NRF_TIMER_EVENT_COMPARE5 : 
        ...
        break;    
    default:
        LOG_INF("Unknow event type %d",event_type);
    }
}

There is a continuous event generated with event_type = 0. It seems that the system is never clearing the interrupt flag?  

removing the nrfx_timer_init does not change anything. Removing the IRQ_DIRECT_CONNECT will result in kernel errors.

Hi Bob

I still don't think it is correct to refer to the bus_timer_event in the call to IRQ_DIRECT_CONNECT. Did you try to replace this with nrfx_timer_4_irq_handler instead?

I tried to set up a simple example with all 6 compare events, and it seems to work fine here: 

I get the following log output, as expected:

*** Booting Zephyr OS build v2.7.99-ncs1-1  ***
Timer 1 callback 0. Counter = 0
Timer 1 callback 1. Counter = 1
Timer 1 callback 2. Counter = 2
Timer 1 callback 3. Counter = 3
Timer 1 callback 4. Counter = 4
Timer 1 callback 5. Counter = 5

Please ignore that it says "Timer 1" in the log, I based the code on an existing sample using timer 1 instead of timer 4. 

Best regards
Torbjørn

Hi Torbjørn,

I implemented your suggestion and was able to narrow down the problem. In the original code, there is a statement under NRF_TIMER_EVENT_COMPARE4 event, that changed the NRF_TIMER_CC_CHANNEL5: nrfx_timer_extended_compare( &bus_timer, NRF_TIMER_CC_CHANNEL5, 16300 + rand(), 0, true );  

This will be a source of the problem, but only if the log level is LOG_LEVEL_DBG. When I change the log level to LOG_LEVEL_ERR it seems to work....

Hi Bob

It is good to hear you found the problem. I didn't quite understand what the problem was though...

Do you mean the problem is in one of the Zephyr drivers, or in your own application code? 

If you think there is a problem in our code we should follow it up, and see if this is something that can be fixed in a future update. 

Best regards
Torbjørn

Hi Bob

It is good to hear you found the problem. I didn't quite understand what the problem was though...

Do you mean the problem is in one of the Zephyr drivers, or in your own application code? 

If you think there is a problem in our code we should follow it up, and see if this is something that can be fixed in a future update. 

Best regards
Torbjørn