nRF51: Extending the IoT-MQTT example

[mr91]

Hello,

I need a little help regarding IoT-SDK 0.8.0 on nRF51. In the MQTT-Example connection to the broker is established only when I press the button (callback), but not when I call mqtt_connect() directly with same set of parameters after recognizing IPV6_UP (absuing m_display_state for that, because I still need some time to get familiar with the firmware).

Can anyone help me with this?

if(false == m_connection_state)
{
  if(LEDS_IPV6_IF_UP == m_display_state)
  {
    mqtt_connect_t param;
                
    param.broker_addr    = m_broker_addr;
    param.broker_port    = APP_MQTT_BROKER_PORT;
    param.evt_cb         = app_mqtt_evt_handler;
    param.device_id      = m_device_id;
    param.p_password     = NULL;
    param.p_user_name    = NULL;

    UNUSED_VARIABLE(mqtt_connect(&m_app_mqtt_id, &param));
  }
}

Thank you very much in advance!

Regards

[mr91]

Today I tried the timer of SDK 8.1.0.

I tried to implement the timer from the example:

nrf_drv_config.h:

#define TIMER1_ENABLED 1 

Timer0 seems to be not available when a Softdevice is present.

main.c:

const nrf_drv_timer_t MYTIM = NRF_DRV_TIMER_INSTANCE(1);
...

err_code = nrf_drv_timer_init(&MYTIM, NULL, mytim_event_handler);
time_ticks = nrf_drv_timer_ms_to_ticks(&MYTIM, 2000);
nrf_drv_timer_extended_compare(&MYTIM, NRF_TIMER_CC_CHANNEL0, time_ticks, NRF_TIMER_SHORT_COMPARE0_CLEAR_MASK, true);
nrf_drv_timer_enable(&MYTIM);

The callback function:

void mytim_event_handler(nrf_timer_event_t event_type, void* p_context)
{

      
    switch(event_type)
    {
        case NRF_TIMER_EVENT_COMPARE0:
        {
          __asm("nop");
        }
        break;
       
        default:
        break;
    }    
}

I expected, that the event NRF_TIMER_EVENT_COMPARE0 is triggered every 2 seconds (2000 ms). Unfortunately, it is called almost instantaneous after starting the program without the delay. Same result when I activate the breakpoint during running execution of the program. I also tried Timer2 instead of Timer1 with the same result.

Can you help me?

Regards

[Krzysztof Chruscinski]

TIMERs is probably by default set to run on 16MHz so 2000ms is just too long period and timer wraps (TIMER1 and TIMER2 are 16bit on NRF51). If you want to has 2000ms on 16bits you need to reduce frequency of the TIMER. It is done in nrf_drv_timer_config_t that needs to be provided to nrf_drv_timer_init (in your example there is NULL provided which meant default configuration).

nrf_drv_timer_config_t config = NRF_DRV_TIMER_DEFAULT_CONFIG(1);
config.frequency = NRF_TIMER_FREQ_31250Hz;