Strange behaviour of nrf52840-DK with NUS

[pdcampo]

I have some experience working with nrf52840-dk and the SDK working in custom projects taking as initial point the different examples of the SDK. 

The problem is that I have just bought two new nrf52840-dk and these board have a strange behaviour that the rest of my dk boards doesn't have with the standard NUS example (SDK version 15).

With the new boards if I write something (ending with CR and LF) through a uart terminal the message doesn't print in the other terminal. It only appears when I write a new message but this new message only will appear with a new one. 

This doesn't happen with the rest of my boards with the same hex application and softdevice. 

Any idea that bring light on this?

Many thanks. 

[pdcampo]

I also have checked that the version within the Debug chip is also the same between the new boards and the old boards. Any idea? Thanks 

[Einar Thorsrud]

Hi,

It only appears when I write a new message but this new message only will appear with a new one.

I am having problems understanding the conditions. Can you elaborate?

[pdcampo]

Of course, sorry.  I'll try to summarise:

- I turn on the two boards (one central and one peripheral with NUS example of SDK version 15)

- Using a terminal program (putty, Coolterm) I write a string array to peripheral board ending with CR and LF. For example: hi world\r\n

-This message don't appear in central board. (If I use other pair of nrf52840-DK boards with the same application and softdevice it does).

- If I write a new string array (for example: I said hi world\r\n) to peripheral board the last message will appear in the terminal of central boards. In this case hi world\r\n.  

The same happens in the direction central -> peripheral with this pair of boards. If I replace one with other nrf52840-DK that I have this problem remain only in one direction.

any idea? Thanks!

[Einar Thorsrud]

Hi,

I see. That seems very odd, and I don't have any explanation at this point. Which version are the boards you are testing with (both the old and new)? You can see the version printed on the white sticker on the largest IC on the DK.

[pdcampo]

All my old boards are revision 0.12.0 and the new ones are 1.0.0