nRF52840 - giving userdefined function at PPI task end

[Aliasgar Surti]

Hello,

We were just wondering if it is possible to give user-defined function at the PPI TEP instead of starting timer or generating some GPIOTE task.

Is it possible to configure a PPI channel where there is a GPIOTE event and as per the occurrence of that event, some userdefined function executes?

nrf_drv_ppi_channel_assign(m_ppi_channel1,
                           gpiote_event_addr,
                           &user_defined_function);

I tried above way, it compiled but the function is not getting executed on GPIOTE event.

I can't use the timer interrupt for this as the frequency of GPIOTE event is really high (around 3MHz). And I want to capture 8-bit parallel port data in 'user_defined_function'

So, Can I make above logic work anyhow? Is it possible in PPI? Any suggestions how can I achieve this one?

Thanks in advance.

[Aliasgar Surti]

I added below line of code in IRQ Handler.

NRF_EGU1->TASKS_TRIGGER[0] = 0;

But still there is no change in behaviour. It continuously executes the IRQ handler and none of the other logic is executed.

Is there any document for clock cycle, such that we can understand the machine cycle consumed in each instruction?

[Edvin]

can you try to trigger the PPI event less often, i.e. have an input pulse with a lower frequency to see if this is actually the issue? (you can use a timer to generate a pulse on one of the GPIOs that you input to your PPI pin)

[Aliasgar Surti]

I don't think that is the issue, this is because when I remove the input pulse from the GPIO then also the counter keeps on increment.

I tried with timer of 10ms. Then also, when first event occurs at PPI event end, the execution of SWI1_EGU1_IRQHandler() starts endlessly. If I remove the input pulse at runtime (by removing input from GPIO pin) then also the counter keeps on increment.

[Edvin]

Is it possible to reproduce this on a DK? If so, would it be possible to send a project that can reproduce this, so that I can test it and see what's going on?

Best regards,

Edvin

[Aliasgar Surti]

Yes, it is possible to reproduce on DK. Timer interrupt toggles pin 0.05 on DK and EGU is triggered by the event on pin 0.02

Attached is the project.

Thanks.

nrf52-ble-image-transfer-demo.zip