How to drive SW_CTRL0 low with CONFIG_NRF700X_RADIO_TEST_COMBO for Bluetooth radio (v2.6.1)

[responsible_duck]

Hello,

When we try to run the standard radio tests for bluetooth, we get really low power compared to what is expected (difference of about 32db). Turns out SW_CTRL0 was driving high by default even though there is no WiFi connection and we are not operating Wifi tests simultaneously (although CONFIG_NRF700X_RADIO_TEST is enabled). 

From the nRF7002 v1.2 spec, page 23 has a note saying:

The behavior of SW_CTRL0/1 is programmable and dependent on the configured coexistence mode and switch control interface.

In that case, how can we switch SW_CTRL0 to low for the bluetooth tests?

[responsible_duck]

I see there is this method but it requires CONFIG_NRF700X_RADIO_COEX=y. It looks like I can't enable it directly. 

Looks like I need to define nrf_radio-coex in device tree. Do I need to use nrf-gpio-forwarder to forward pins?

nrf_radio_coex: nrf7002-coex {
    status = "okay";
    compatible = "nordic,nrf700x-coex";
    req-gpios = <&gpio0 28 GPIO_ACTIVE_HIGH>;
    status0-gpios = <&gpio0 30 GPIO_ACTIVE_HIGH>;
    grant-gpios = <&gpio0 24 (GPIO_PULL_DOWN | GPIO_ACTIVE_LOW)>;
    swctrl1-gpios = <&gpio0 29 GPIO_ACTIVE_HIGH>;
    btrf-switch-gpios = <&gpio1 10 GPIO_ACTIVE_HIGH>;
};

[responsible_duck]

This doesn't seem to work. Do I need to remove all Wifi configs including the Wifi radio testing in order to have it switch to bluetooth automatically?

[Elfving]

Hello,

I will have to get back to you on this tomorrow unfortunately.

Regards,

Elfving

[responsible_duck]

ok thanks

[Elfving]

So you want to run this test for BLE with Wi-FI coex still enabled? And I am getting the impression from your other case that you are running this test on the netcore?

Any particular reason why you do not simply want to run this without coex enabled? I do not see why you would need wifi coex for the test.

Regards,

Elfving

[responsible_duck]

The primary doubt I have for this case is why SW_CTRL0 is driven high in the combo radio test build even when wifi radio testing functions are not actively used. We are trying to use the bluetooth radio test functions in this combo radio test build but not seeing the expected power because SW_CTRL0 is always enabling wifi antenna. 

We assumed maybe enabling coex would enable some functions to switch antenna (ie the `sr_ant_switch` method) like below: