board configuration BT840F.

[shlomots]

my costom board is based upon the BT840F fanstell board.
I know that this board is based on the nrf52840 QIAA SOC. 
but I also understand that nrf52840 QIAA has different configurations as I see here:
 https://docs.nordicsemi.com/bundle/ps_nrf52840/page/ref_circuitry.html
how can I know which configuration BT840F uses? 
is it the same as the nrf52840dk?

thanks in advance, 
-Shlomo

[Sigurd Hellesvik]

Hi,

The configuration depends on how Fantell have set up their circuit design for the BT840F.

For an explanation of the Fanstell module, I recommend that you contact Fanstell, or see if you can find any circuit diagram for the BT840F. If you find such a schematic and post  it here, I can help you identify the configuration form the schematic

Regards,
Sigurd Hellesvik

[shlomots]

BT840F_BT840N+Product+Specifications.pdf
thank you, 
does this suffice?

[Sigurd Hellesvik]

I do not find exactly what I need there, but maybe I can help you either way.

how can I know which configuration BT840F uses? 

Why exactly do you need to know this? What is the thing you will do differently based on this?

[shlomots]

I am trying to use pin09, of port 0.
from what I learned, on the dk you cant use this pin for general purposes without adding this to the device tree 

&uicr {

    nfct-pins-as-gpios;

};
and adding a solder bridge.

but on a custom board, 
this: 

&uicr {

    nfct-pins-as-gpios;

};
should suffice.
Still, I am not able to use this pin with my app.
this is a simple app that sends chars through uart and I know that with unreserved pins on the dk it works ok.
It also works on my custom board if I use different pins, just using pin 9 doesn't seem to work.
I have a codebase that works with the old SDK in which we were able to use this pin. are there any additional steps that should be taken in order to use this pin on the BT840F with the new SDK?

[Sigurd Hellesvik]

Thanks for explaining the use-case, this makes it much more clear to me!

I cannot see anything on the BT840F module that says this should not work.

Can you check the following file for you custom board: build/<project>/zephyr/zephyr.dts and verify that nfct-pins-as-gpios; is set here? This is the build output file, so this way we can check if the configuration was successful in the build.

[shlomots]

in the end, It was just a problem with my code logic. 
I tried to set that pin with the value 1 as a test and forgot about it, that messed the communication up I guess.
Thanks for the support Sigurd!