RE: Behavior of SW_CTRL0 on NRF7001

Priyanka — Tue, 17 Sep 2024 07:04:10 GMT

Hi Nils,

[quote user=""]What is the default behavior of the SW_CTRL0 pin? In the image above it looks like the NRF7002 is setting SW_CTRL0 high whenever it wants to send.[/quote]

The SW_CTRL0 pin behaves like an output control signal that is set high when the nRF7002 needs to switch to the WiFi antenna, usually when it is transmitting. This is in order to control an external antenna switch (like the one in the schematic) so that the correct radio (WiFi or Bluetooth) has access to the antenna at any given time.

[quote user=""]Can this behavior be changed?[/quote]

Yes, this behaviour is programmable : https://docs.nordicsemi.com/bundle/ps_nrf7002/page/chapters/functional/doc/coexistence.html#:~:text=The%20behavior%20of%20SW_CTRL0/1%20is%20programmable%20and%20dependent%20on%20the%20configured%20coexistence%20mode%20and%20switch%20control%20interface.

[quote user=""]Is there any Nordic-specific setup of the coexistence interface I have to do in Zephyr?[/quote]

Zephyr has support for WiFi and Bluetooth coexistence through the 3-wire or 4-wire coexistence interface (typically SW_CTRL0 and SW_CTRL1 for antenna switching). Nordic provides coexistence drivers in the nRF Connect SDK that helps manage this. You need to define the correct coexistence mode in your device tree and configure the coexistence settings for the nRF7002 within the WiFi driver.

-Priyanka