Can nrf5340 network core and application core share SPI bus pins?

[dstarling]

I am working on a custom board that currently has an nRF21540 that is connected on the SPI bus of nRF5340, that is also connected to a number of SPI slave devices controlled by the Application Core.

The nRF21540 would need to be controlled on SPI via the Network Core of the nRF5340 (Currently I am using it in GPIO mode only).  it seems that without some mechanism to control access that both cores cannot access the same SPI bus pins.  Could you please confirm if this configuration could work? Or must the nRF21540 must be on a separate SPI bus?

[Sigurd Hellesvik]

Hi,

The network core and the application core have different SPI peripherals.

The nRF5340 does not have any HW or drivers to allow smooth switching between appcore SPI and netcore SPI, if these were to use the same pins.

I see three alternatives:

• Use different pins for different SPIs
• Implement logic in your appcore and netcore applications to turn off and on SPIs so they do not use the pins at the same time.
• Use netcore SPI for all SPI communication

Regards,
Sigurd Hellesvik