PWM implementation for dimming.

[DeveloperZ]

Hi,

I tried adding PWM for turning on/off the LED's on the DK for the Enocean switch example. It worked well.

I tried to perform dimming on the switch example by restricting the increasing or decreasing brightness using the RELEASE_ACTION as follows.

       if (p_status->b0 && timer_diff(timestamp, m_switch_state[index].b0_ts) > SWITCH_DEBOUNCE_INTERVAL_US)
        {
            m_switch_state[index].b0_ts = timestamp;
            set_params.on_off = APP_STATE_ON;
            app_pwm_enable(&PWM1);	
            for (uint32_t i=90; i > 50; i--)
                     {
			while ( app_pwm_channel_duty_set(&PWM1, 0, i) == NRF_ERROR_BUSY);
                        nrf_delay_ms(100); 
                        if(p_status->action == RELEASE_ACTION) 
                            { 
                                break; 
                            }
                     }
              status = generic_onoff_client_set_unack(&m_clients[1], &set_params, &transition_params, APP_UNACK_MSG_REPEAT_COUNT);
        }

But when I release the button to stop the dimming, the release action is not getting recorded immediately. I can see the release action after the PWM is implemented completely(till duty cycle of 50). How can I solve the issue to stop the dimming once I release the switch. I know that the experimental_dimming example contains generic level model but I would like to know why this code isn't functioning properly.


Thank you.

[Mttrinh]

Hi,

Where in you code are you running this? Are you running this inside a handler?

I suspect that p_status won't be updated, so it won't stop until the for-loop is done. Maybe an easier way of doing this, will be to check the button value instead. You can have "1" for pressed and "0" for released, then stop the dimming if the button value is "0".

Best Regards,

Martin

[DeveloperZ]

That code mentioned was running inside the app_switch_debounce() function.

I realized that the delay function is keeping the processor busy and it isn't allowing the processor to check for the press action of the enocean switch. 

How can I perform dimming without using a nrf_delay_ms() function so that the process can be interrupted in between with the release action?

Thank you.

[Mttrinh]

Yes, as you said nrf_delay_ms() will hold up the CPU from doing anything. If you want to use a timer, you can instead use app_timer.

Best Regards,

Martin

[DeveloperZ]

Hi,

We tried to implement the timer but it didn't work, the command  p_status->action == RELEASE_ACTION isn't getting updated until the static void app_switch_debounce() function is finished executing. My colleague started a thread related to this last night: https://devzone.nordicsemi.com/f/nordic-q-a/40106/enocean-mesh-example-for-dimming-using-pwm

Any idea on how to implement it?

Thank you.

[Mttrinh]

I think it is because they have the same priority level, which means that p_status won't be updated until app_switch_debounce() is done. Instead of using p_status->action == RELEASE_ACTION, maybe you can try the suggestion in my first reply?