KW45 board antenna switch

[chetan98]

Dear NXP Team

I have KW45 EVK board as well as I have KW45 LOC board I was using kw45 EVK sdk for both when I flashed eatt central code in kw45 LOC board and from evk sdk code was working but1 I want to confirm from NXP as EVK board only have one inbuilt antenna how code design for evk is working in LOC board as how to switch antenna for EVK from internal to external NXP can confirm is it be down by software or hardware changes

2 In LOC board USED EATT CENTRAL CODE want to use J7 and connect external antenna and I added one function BOARD InitRFSwitchControlPins in eatt central and changed the antenna from A to J7 in software but without connecting external antenna I am receiving data from BLUETOOTH how it is possible please see the image for reference

chetan98_0-1758191004111.png

Can NXP confirm both the point mentioned above, and like only software or hardware software both changes are required in both EVK or LOC board

Thanks 

Chetan

[chetan98]

Thank you Luis!!! Appreciate your efforts.

[chetan98]

Thanks Luis

[chetan98]

Thanks Luis!! If I will disable all pin config than also data will come?

Secondly If I have not connected external antena and device is not configured for internal antenna also how data can come could you please explain?

Thanks 

Chetan

[chetan98]

NOTE;For your 3rd point you can check pin mux.c file in wireless uart example code in LOC board SDK.you will find the function for antenna switch 

[luis_maravilla]

Hello Chetan

Could you help us confirm what implementations were made in code to migrate the eatt_central example from the KW45-EVK SDK code to KW45-LOC?

For have a better understanding about your question, Could you kindly explain if you want to know how to set an external antenna in KW45-EVK?

Could you help us confirm what are the changes and where are they located in the code for changing the Antenna from A to J7 in software and adding the BOARD_InitRFSwitchControlPins? For us to try replicate the scenario

Best Regards

Luis

[chetan98]

Hello 

Thanks for quick reply 

1.For conversion of eatt central from evk to Loc I installed latest LOC board sdk and compiled the code in MCU expresso and made it LOC board compile and code is working on LOC board.

Is this method correct?

2.I want to know for both the board KW45 evk board as well as Kw45 LOC board , 

And can you tell me is only software changes are required in both board?

With regards

Chetan

[luis_maravilla]

Thank you for the information. The recommendation its using an KW45-LOC example code from SDK as base for the configurations and avoiding compilation errors, and then modifying to your application needs.

For enable the SMA Antenna connector,

KW45B41Z-EVK:

By default, the inverted-F antenna is enabled, and the SMA connector is disabled. The inverted-F antenna can

be disabled and the SMA connector can be enabled by moving the 15-pF capacitor from C3 to C4 (DNP) [Hardware Change].

I would recommend checking the KW45B41Z-EVK Board User Manual chapter 2.7 RF Interface for checking configurations and RF circuit diagram.

KW45B41Z-LOC:

The KW45B41Z-LOC board provides the following RF input/output (I/O) ports for communication with the 2.4 GHz radio of the target MCU: • Two U.FL connectors (J7 and J8) (20279-001E) • Two RF chip antennas (ANT_A and ANT_B).

Only one of these I/O ports is selected for communication at a time. The KW45B41Z-LOC board provides an SP4T RF switch U2 (HSWA4-63DR) to make this selection. The software changes its mentioned in Table 14 from KW45B41Z-LOC Board User Manual no HW changes needed.

[chetan98]

Hello,

I am using LOC evk example, and I am considering for antenna switch only changes are required in the part which I am mentioning below can you please confirm?

chetan98_0-1758520883572.png

because in document just switch information is given and need to change what is configuration of the pin required.

I did following changes in pinmux.c can you please confirm it is correct for J7 and only changes are required in pinmux.c

chetan98_1-1758521108843.png

chetan98_2-1758521170186.png

I want to use J7, after doing this configuration mentioned in the document for J7 without  connecting external antenna I was receiving data over BLE in LOC board, is it predictable behaviour?

I did following changes in Pinmux.c can you please check only changes are required in this part only for using external antenna.

chetan98_4-1758521524110.png

Thankyou 

Chetan

[luis_maravilla · Accepted solution]

Hello Chetan, Sorry for the late response

The pin configuration is right for using RF1 mode, Only the changes made in BOARD_InitRFSwitchControlPins [ pin_mux.c] are required.

Receiving data over BLE it’s the expected behavior. I test the configuration made in w_uart example.

Best Regards

Luis

[chetan98]

okay Luis but without using external antenna when internal antenna is off ,how it is possible I am receiving data can you explain.

[luis_maravilla]

Hello Chetan,

For receiving data without an antenna; The exposed U.FL pad and PCB traces can unintentionally act as a weak antenna; also, BLE receivers are very sensitive, while is not the intended use for the configuration using it without an antenna, it can receive data in short range reception.

Best Regards

Luis