Questions on NFC examples for nRF52840 PDK

[Pema]

Hi,

I am testing NFC on the nRF52840 preview kit that I have (PCA10056, v0.9.2) using the included NFC antenna. I am running the pre-compiled examples from the 16.0.0 SDK together with my Samsung S9 phone. I have tested the record_url and record_text examples and my feeling is that sometimes it works and sometimes it doesn't, even though I try to place the phone at the same position relative to the NFC antenna of the PDK. I can get a few good readings in a row but other times there are attempts where nothing happens regardless on how the phone is placed, almost as if there is some time out... Is this the expected behavior? Is there some time-out in the 840 (or in the phone) that prevents readings at certain circumstances?

/Peter

[Edvin]

Hello Peter,

 

I can get a few good readings in a row but other times there are attempts where nothing happens regardless on how the phone is placed, almost as if there is some time out...

What example is this happening on? Do you use any BLE at the same time?

What happens when you don't get the "good readings"? Do you see any corrupted messages? How about the log? Do you see anything in the log?

Best regards,

Edvin

[Pema]

Hi Edvin,

I used the record_text example mostly, coming from examples folder under SDK 16.0.0 folder (so I guess BLE is not used at the sime). By good readings I mean a successful NFC transaction => "Hello World" appears on the phone. An unsuccessful reading results in nothing. I can get several good ones in a row by moving the phone in and away from the PDK NFC antenna, but now and then it seems to fail and there is no results even though the phone is positioned roughly the same as during a successful try. The messages are either ok (Hello world) or nothing. Where can I find the log? I don't have JTAG or similar, I just program the device using the pre-compiled hex files through the USB device in Windows file manager. How critical is the timing, i.e. the time the phone remains over the NFC antenna of the PDK?

/Peter

[Edvin]

Pema said:

I don't have JTAG or similar

 You can see the log if you do one of the following:

If you use SES, go to sdk_config.h of the project, find and change the define for:

#define NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 1

to

#define NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 0

And start a debug session in SES.

If you do not use Segger Embedded Studio, you can download and start Segger RTT Viewer.

BR,

Edvin