Dynamic changing of the MODE pin on the nrf21540

RE: Dynamic changing of the MODE pin on the nrf21540

Einar Thorsrud — Mon, 18 Mar 2024 13:49:59 GMT

Hi,

[quote user="pquevedo"]sd_ble_gap_tx_power_set(). I don't think this would be related to the MODE pin on the 21540 though?[/quote]

No, that is correct. I think Ketil's point was that this is a way that will give you the same result more easily and with less room for error. If you reduce the input power to the FEM by reducing the output power of the nRF using sd_ble_gap_tx_power_set(), this will also reduce the output power from the FEM by the same ammount. So there is no need to do anything with the MODE pin in this case.

Alternatively, if you want to control the MODE pin, you are free to do that with a GPIO like any other GPIO. As indicated in the product specification, You should never adjust the gain configuration while transmitting, so this shoud be controlled by the nRF that use it and you can use for instance radio notifications in order to know when the radio is active. And if this is initiated by the other BLE seoc, it must signal to the nRF that it should reduce the output power (effectively makign a form of custom coexistance interface).

RE: Dynamic changing of the MODE pin on the nrf21540

pquevedo — Thu, 14 Mar 2024 13:33:14 GMT

[quote userid="2125" url="~/f/nordic-q-a/109250/dynamic-changing-of-the-mode-pin-on-the-nrf21540/473873"]In what occations would you like to change the MODE pin? [/quote]

We have 2 BLE SoCs on a particular board. One of them is constantly running with the 21540 FEM. The other comes online very rarely and for relatively short periods of time for other reasons. When the other SoC comes online we want to change the 21540 from +20 to +10 until the second chip is done whatever it needs to do.

[quote userid="2125" url="~/f/nordic-q-a/109250/dynamic-changing-of-the-mode-pin-on-the-nrf21540/473873"] The application can handle this the same way as you set the output power. [/quote]

Can you clarify? Using the nrf5_sdk there is a specific API call to the soft-device to change output power (when not using the 21540 FEM) with no special synchronization required. sd_ble_gap_tx_power_set(). I don't think this would be related to the MODE pin on the 21540 though?

RE: Dynamic changing of the MODE pin on the nrf21540

ketiljo — Thu, 14 Mar 2024 13:20:34 GMT

In what occations would you like to change the MODE pin? The application can handle this the same way as you set the output power.