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Default SPI pins from examples provided are "Standard drive, low frequency I/O only"

Hi,

I saw on this answer that the pins for SPI should be chosen among non  "Standard drive, low frequency I/O only". But from the default ones only SCK is not low frequency pin, rest are. Why this is the case?

Default pin assignment:

SPI_SCK_PIN 26

SPI_MISO_PIN 30

SPI_MOSI_PIN 29

SPI_SS_PIN 31

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  • Hello,

    But from the default ones only SCK is not low frequency pin, rest are. Why this is the case?

    By default pin assignment I assume you are referring to the pin's in the SPI examples?
    If so, this is done because the SPI examples in the SDK does not use the SoftDevice (or any radio functionality for that matter) - so you are then free to disregard the low-frequency recommendation, since the signal on these pins will not degrade radio performance anyways.
    Theoretically, while any of the GPIO's could have been used, a lot of them are already in use for other functionality on the DK.

    Please be advised that any GPIO's can be used for the SPI peripheral, but you should follow the guidance of the referenced Pin Assignment in the Product Specification to avoid degrading radio performance.

    Best regards,
    Karl

Reply
  • Hello,

    But from the default ones only SCK is not low frequency pin, rest are. Why this is the case?

    By default pin assignment I assume you are referring to the pin's in the SPI examples?
    If so, this is done because the SPI examples in the SDK does not use the SoftDevice (or any radio functionality for that matter) - so you are then free to disregard the low-frequency recommendation, since the signal on these pins will not degrade radio performance anyways.
    Theoretically, while any of the GPIO's could have been used, a lot of them are already in use for other functionality on the DK.

    Please be advised that any GPIO's can be used for the SPI peripheral, but you should follow the guidance of the referenced Pin Assignment in the Product Specification to avoid degrading radio performance.

    Best regards,
    Karl

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