nRF21540 implementation questions

RE: nRF21540 implementation questions

Andreas — Wed, 13 May 2020 07:42:40 GMT

Hi,

The 'recommendation' is only if the pin is configured as high-drive and there is high-frequency toggling during radio operation, on some pins this may affect some radio performance parametres like e.g. RX sensitivity. Apart from this we recommend using the pins that are optimal for your layout, and when using the TXEN/RXEN control this will not be a concern, so using the pins you mention is perfectly fine.

Best regards,

Andreas

RE: nRF21540 implementation questions

Angelo — Tue, 12 May 2020 22:05:40 GMT

I noticed that some pins on the nRF52840 are recommended for SPI, but for optimal layout I would like to use different digital pins (particularly P0.06, P0.08, P1.08, P1.09). Are there any concerns doing this?

RE: nRF21540 implementation questions

Andreas — Mon, 11 May 2020 08:01:56 GMT

Hi,

Yes that is fine.

Best regards,

Andreas

RE: nRF21540 implementation questions

Angelo — Fri, 08 May 2020 16:06:10 GMT

Thanks Andreas. If I'm only using one antenna, can I just leave ANT_SEL pulled low, and ANT2 unterminated?

RE: nRF21540 implementation questions

Andreas — Fri, 08 May 2020 13:21:52 GMT

Hi,

You do not need to use SPI, but you will then not be able to tune the TX gain, but if you do not want/need to do this you can use the TXEN/RXEN pins.

You would need your stack to control the pins as you say to have it toggle between TX and RX. The NCS BLE controller must be configured to do this. Some pins can also be tied high or low if a static state is wanted, saving pins. This is also the case for TXEN or RXEN if you want the FEM to only stay in TX or RX for your application.

Best regards,

Andreas