Does the GPIOTE effect the GPIO pin configuration in particular the drive I need to keep it Disconnect 0

Hi

Using PCA 10040A , SDK 16.0.0 and Segger Studio.

I would like to generate a short accurate *** on a GPIO , probably 250 nano seconds duration. So I am looking at using the GPIOTE feature.

However I need to keep the GPIO drive configuration as 

"NRF_GPIO_PIN_D0S1 = GPIO_PIN_CNF_DRIVE_D0S1, ///< !< Disconnect '0' standard '1'." 

So that when its low there is no drive its effectively Open Collector

The GPIOTE doc says that it takes over the GPIO and it says "When the GPIOTE is disconnected from a pin, see MODE field in CONFIG[n] register, the associated pin will get the output and configuration values specified in the GPIO module."

This suggests that my drive configuration maybe changed by the GPIOTE module

Can someone confirm this please and if its correct can anyone suggest an alternative to using the GPIOTE/PPI feature

Robin

We need to generate a precise pulse on a GPIO in nanoseconds that is with 16MHZ clock 62.5ns resolution , will typically be multiples of this.

I was thinking of using the GPIOTE to get the precision, however the GPIO being used is configured as 

   

So effectively Open Collector when LOW we need the GPIO to be in this state when LOW. 

When you configure the GPIOTE it takes over the GPIO and the configuration no longer applies.

We need to take the HIGH GPIO for a precise period and then return to the LOW Disconnected state when finished.

Any ideas how we can do this, I did think of using a timer but reading other posts there is a lot of inaccuracy in doing it that way

Thanks

Parents
  • Hi Robin

    You should be able to change drive settings even if the GPIOTE module is connected to a pin. 

    If you look at figure 1 here you can see that there are OVERRIDE signals for pin direction, out pin state and input connection, allowing peripherals such as the GPIOTE module to override the settings you configure, but DRIVE settings are not covered by this. 

    In other words the drive settings should still be available for you to change. 

    If you are having issues getting this to work let me know, and I will have a look. 

    Best regards
    Torbjørn

Reply Children
Related