nrf21540 interface to 528xx

Hello Jorgen,

We do not have any schematic that shows interface between nRF21540 with nRF52840. But you can find hardware file of nRF21540 here. nRF21540 DB - Downloads - nordicsemi.com

You need to have all the control lines (e.g. rx, tx, power down etc) and the spi interface connected up to the nRF52840, because the software implementation use both.

Best Regards,

Kazi Afroza Sultana

Hello Jorgen,

We do not have any schematic that shows interface between nRF21540 with nRF52840. But you can find hardware file of nRF21540 here. nRF21540 DB - Downloads - nordicsemi.com

You need to have all the control lines (e.g. rx, tx, power down etc) and the spi interface connected up to the nRF52840, because the software implementation use both.

Best Regards,

Kazi Afroza Sultana

Yes, eval board schematics works fine. Didn't realize you had the 21540 chip on the 21540 DB pcb actually.
Are you working on Qestions : 2-5?
(I haven't received 21540 DB I ordered yet)

Hello,

You can look at this documentation about working with RF fron End Module https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/ug_radio_fem.html#

2.Are all the drivers for TX and RX signals etc. to 21540 interface are available in the examples and SDK?

yes

3. Can I use K-config in VS to configure 21540 including gain parameter?

yes mostly the device tree is used for this.

4. Is the configuration for the 21540 being written through the 52840 SPI?

yes

5.  Can I write the USB port of the 52840 chip to set the gain on 21540 (not using Jlink debugger) and how?

According to our expat in team 

 It's technical feasible, but we don't have any samples that show-case this, and MPSL is also currently missing features for adjusting output power dynamically.

Thanks.

Best Regards,

Kazi Afroza Sultana

Thanks Kazi for answers.

1. When you say you can't change gain "dynamically",
   I assume you you referring to the changing gain on 21540 during runtime of an application?
2. If I stop application I should be able to change Gain parameter on 21540, right? I.e I don't have to reset the device, right?
3. If I set a "fix gain" on 21540 to achieve total of +19dbm I assume I can dynamically reduce output power on 52840, through the 52840 USB port, right?
   This is not something "technically feasible" it already works, right?

Sorry if these are fundamental questions. Just want o make sure I don't spend days on trying to make something work if not supported yet.

Thank you!
Jorgen

Hello Jorgen,

1. When you say you can't change gain "dynamically", I assume you you referring to the changing gain on 21540 during runtime of an application?

yes

2. If I stop application I should be able to change Gain parameter on 21540, right? I.e I don't have to reset the device, right?

It would be possible , you need to reset the device. 

3. If I set a "fix gain" on 21540 to achieve total of +19dbm I assume I can dynamically reduce output power on 52840, through the 52840 USB port, right?

You can change the tx power on the nRF52, you can see this  https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/bluetooth/hci_pwr_ctrl  samples of hci_pwr_control where dynamic Tx power controls over the LL of the BLE controller via Zephyr HCI VS command. A peripheral advertises by varying the TX power. The initial TX power is the default power set for the application in Kconfig. Later the TX power variation of the peripheral device varies from -4dBm to -30dBm where the power level decreases every 5s. However , we do not have any sample that does this through USB. 

There is a sample https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/subsys/usb/cdc_acm  which demonstrates use of a USB communication Device Class (CDC) Abstract Control Model (ACM), received data from the serial port the serial port is echoed back to the same port provided by this driver.  

It should be possible to combine so that you can send commands though USB.

Thanks.

Best Regards,

Kazi Afroza Sultana