Changing GPIOTE out pin level gives hard fault

RE: Changing GPIOTE out pin level gives hard fault

SmallerPond — Tue, 02 Mar 2021 18:13:37 GMT

There you go! I didn't even see that little guy all the way at the bottom of the header :-P

Thanks!

RE: Changing GPIOTE out pin level gives hard fault

Kenneth — Tue, 02 Mar 2021 17:55:06 GMT

Can you try to use nrfx_gpiote_clr_task_trigger() instead?

Kenneth

RE: Changing GPIOTE out pin level gives hard fault

SmallerPond — Tue, 02 Mar 2021 17:40:30 GMT

Works for me - I wasn't sure if I was missing something obvious.

RE: Changing GPIOTE out pin level gives hard fault

Kenneth — Tue, 02 Mar 2021 16:57:21 GMT

The GPIOTE peripheral is controlling the pin, so even if you tried calling nrf_gpio_pin_clear/set it would not have any effect. Similar to if the SPI or TWI was controlling the pin, the nrf_gpio_pin_clear/set would have no effect.

[quote user="SmallerPond"]So why have nrfx_gpiote_out_clear/set at all? If I'm not using the TE part of GPIOTE, I would just use nrf_gpio_pin_clear/set.[/quote]

I agree, that is confusing, I think there may be some historic reasons.

Kenneth

RE: Changing GPIOTE out pin level gives hard fault

SmallerPond — Tue, 02 Mar 2021 15:25:22 GMT

I think the thing that's so confusing is that if I am using GPIOTE instead of GPIO, then I probably want it for the events system - but then nrfx_gpiote_out_clear is just nrf_gpio_pin_clear but with an assertion that the pin isn't using the events system... So why have nrfx_gpiote_out_clear/set at all? If I'm not using the TE part of GPIOTE, I would just use nrf_gpio_pin_clear/set.

RE: Changing GPIOTE out pin level gives hard fault

Kenneth — Tue, 02 Mar 2021 15:19:18 GMT

Hi,

[quote user=""]Is it to prevent accidentally triggering PPI by manually setting the pin?[/quote]

Looking at the gpiote driver it looks like it has some protection mechanism that prevent using nrf_gpio is not allowed while nrf_gpiote is controlling the pin, which I think make sense, because using nrf_gpio while nrf_gpiote is controlling the pin should have no effect on the output level. So you would need to uninit-init yes, unless you enable toggle task, in which case you could just trigger toggle task to revert the pin back to low level. You can always read the pin level to ensure you don't invert the level on the pin before calling toggle task.

Kenneth