Radio test configuration nrf21540DK

[Muhammad Usman]

Hi JONATHAN LL 

I am using nrf21540DK, NCS version 2.3.0, Radio Test example, RSSI Viewer as a Scanner, and VSCODE studio as an IDE. 

I just come to know that. do not support the nrf21540DK configuration. I tested its RSSI and got -23dm @0 to 4 dbm input from nrf52840.

To confirm the communication between nrf21540 and nrf52840, I used an oscilloscope to monitor the SPI signals on P1.13, 14, and 15. But I got no signal.

After that when I loaded the supported "Direct test mode " example I got the pulses on these pins.

Can you please help me in this regard that how to make it work with the "Radio test" example? 

Above picture is when i tested it with Direct test mode.But no signals in case of radio test example.

Can you please help me in this regard? I tested my custom (nrf52833+nrf21540) board as well .And i faced the same issue with that as well.

Thanks & regards,

Muhammad Usman

[JONATHAN LL]

Update:

Setup with the nRF21540DK, Radio test example, with the following configs:

CONFIG_FEM=y

CONFIG_RADIO_TEST_POWER_CONTROL_AUTOMATIC=n

Using the Saleae logic pro to check the SPI lines. Connected to pin P1.13, P1.14 and P1.15 and I am able to see activity. 

Picture above is captured when the start_tx_carrier command is send.

uart:~$ output_power neg8dBm
TX power: RADIO_TXPOWER_TXPOWER_Neg8dBm
uart:~$ fem tx_gain 0
Front-end module (FEM) Tx gain set to 0
uart:~$ start_channel 40
Start channel set to: 40
uart:~$ start_tx_carrier
Requested tx output power: -8 dBm
Tx output power set to: -8 dBm
Start the TX carrier



This capture is with the below commands, capture is taken when tx_carrier command is sent. 


uart:~$ fem tx_gain 10
Front-end module (FEM) Tx gain set to 10
uart:~$ start_tx_carrier
Requested tx output power: -8 dBm
Tx output power set to: -8 dBm
Start the TX carrier
uart:~$




There is no activity on the SPI lines before the start tx is sent.


Here is a test where automatic power control was enabled



uart:~$ output_power neg12dBm
TX power: RADIO_TXPOWER_TXPOWER_Neg12dBm
uart:~$ start_tx_carrier
Requested tx output power: -12 dBm
Tx output power set to: -30 dBm
Start the TX carrier
uart:~$




For the nrf52833DK with the 21540EK:

SPI works here as well, you can see that there is the same type of action on the different SPI pins here:


uart:~$ start_channel 40
Start channel set to: 40
uart:~$ start_tx_carrier
Requested tx output power: 20 dBm
Tx output power set to: 20 dBm
Start the TX carrier
uart:~$



I have also used a nRF52DK connected to RSSI viewer app to confirm that the DUT is transmitting. 

Regards,
Jonathan

[Muhammad Usman]

Hi JONATHAN LL 

Again thank you for the response!

Today I tested as per your instructions.

CLK and MOSI P1.13, when gain Set to 0 for FEM (nrf21540 DK)

CLK and MISO P1.14 ,when gain Set to 0 for FEM(nrf21540 DK)

CLK and MOSI P1.13, when gain Set to 10 for FEM(nrf21540 DK)

CLK and MISO P1.14. when gain Set to 10 for FEM(nrf21540 DK)

JONATHAN LL said:

So for the custom board do you have easy access to all the pins on the nRF21540?

Sorry in the current version of the custom board (nrf52833+nrf21540), we don't have easy access to all pins.

So can we confirm that nrf21450 is working fine via external Registers using SPI communication? Or do you have any better suggestion to ensure communication other than RSSI value? 

To confirm that the radio test example pin configuration is mapped correctly and will work fine for the custom board. We tested FW on the nrf52833 DK and monitored the Clk and MOSI signals on that. We are getting the same waveform as pasted above for nrf21540 Dk.

Thanks & regards,

Muhammad Usman

[JONATHAN LL]

Muhammad Usman said:

So can we confirm that nrf21450 is working fine via external Registers using SPI communication?

You can check by reading a register of the nRF21540 over SPI yes, but I don't think we have any samples for that. 

So you can use Read from CONREG0 or 1 if you want to confirm that what you think you have been writing to the FEM is what you think it is after you sett whatever write. Or you can just read any readable register to confirm that SPI is working. 

https://infocenter.nordicsemi.com/topic/ps_nrf21540/chapters/device_control/doc/operating_state.html?cp=8_0_0_4_0 



https://infocenter.nordicsemi.com/topic/ps_nrf21540/chapters/spi/doc/frontpage.html?cp=8_0_0_5 


If you need any more help on confirming that you are doing it correctly then just update me here and I will try to make a better example. 

Muhammad Usman said:

To confirm that the radio test example pin configuration is mapped correctly and will work fine for the custom board. We tested FW on the nrf52833 DK and monitored the Clk and MOSI signals on that. We are getting the same waveform as pasted above for nrf21540 Dk.

This should be sufficient to confirm that it works. But if the custom board is not performing as expected and the DK is working fine then there might be something HW related. IF so then we can try to help with that as well

Regards,
Jonathan

[Muhammad Usman]

Hi JONATHAN LL 

Thank you so much for the help! 

Sure I will go through your instructions regarding the SPI registers Read.

JONATHAN LL said:

This should be sufficient to confirm that it works. But if the custom board is not performing as expected and the DK is working fine then there might be something HW related. IF so then we can try to help with that as well

  For this, I have to provide the schematic of Custom HW right ? What should I have to do? to create a private ticket or you will do it on your own?

Thanks again,

Regards,

Muhammad Usman

[JONATHAN LL]

If there are only questions about the design and layout and you do not mind sharing that info with others then a public ticket is fine. Otherwise a privet ticket is best, if there is any need to share shipping details or other sensitive info that you don't want the rest of the world to know about. 


You create the ticket, then name it something along the lines of "HW review request, nRFXXX" add all the relevant info, like schematic and layout files, so that would be the schematic as PDF. For the layout its best to share the GERBER files but a pdf is also fine. If you are using Altium to design the we can use that as well so the PCB and SCH file will do. 

Include description of where and how it will be used and if there are any batteries or similar items then pleas also share where they will be placed.  

Regards,
Jonathan

[Muhammad Usman]

Hi JONATHAN LL 

Thank you so much for the help! 

Let me create a private ticket for that!

Thanks & Regards,

Muhammad Usman