nrf connect programmer error with usb cdc enabled?

[lorenzoFIL]

Hi All,

Noticed a bit of a strange issue with my application on my custom board the other day. It seems that the nrf connect programmer has issues communicating with my device when I have USB CDC enabled, more specifically when I am polling for USB events. Simply commenting the following from my main loop seems to make the problem go away

while (app_usbd_event_queue_process())
    	        {
    	            /* Nothing to do */
    	        }

The errors I see from the nRF programmer seem to vary, but I've seen the following:

Error while probing devices: Error occured when get serial numbers. Errorcode: Could not execute the function due to too many calls in line (0xe)

Error when getting device info: Error: Error: Error occured when read. Errorcode: CouldNotCallFunction (0x9) Lowlevel error: JLINKARM_DLL_ERROR (ffffff9a)

Error when closing nrfjprog: Error: Error occured when close opened device. Errorcode: CouldNotResetDevice (0x5) Lowlevel error: JLINKARM_DLL_ERROR(ffffff9a)

On occasion, and I'm still not sure what the conditions are, but nrf programmer will be able to communicate with my device, and show me the memory layout. HOWEVER, the following error will popup after doing the memory read:

Error when closing nrfjprog: Error: Error occured when close opened device. Errorcode: Could not execute the function due to too many alls in line (0xe)

Seemingly though my application has been working fine. I'm able to perform the tasks I need with the USB port, but yea I just noticed it makes the programmer act funny. Has anyone ever run into this before? I'm having a hard time understanding why polling for USB events would affect the programmer. 

[Sigurd]

Hi,

What J-link programmer are you using ?A stand-alone debugger, or a on-board debugger on a nRF development kit?

What VDD voltage do you have on your custom board? 

[lorenzoFIL]

Hi Sigurd,

I'm using a J-Link Lite (I hope that's what you were asking). Yea, it's a stand-alone debugger.

My VDD on the custom board is 3.3V

[Sigurd]

1) Are you using a USB hub? If yes, is the both the J-Link Lite and the nRF52840 USB connected to this USB hub?

2) Do you see the issue, if you call "nrfjprog --halt" , and then read the memory flash with nRF programmer app ?

[lorenzoFIL]

1) No USB hub!

2) This did not seem to help. 

I've also tried this with the stock USB CDC ACM example and found that it produces the same outcome. Any ideas? I'm wondering if there could be something inherently wrong with my code, but the plus side is that outside of this, my device seems to be functioning as expected. 

[Sigurd]

Hi,

Do you see the same issue if you use nRF52840-DK?

Right now, I think the root cause is with the nrf connect programmer app, it's having some issues with this not being a DK, and/or that a J-Link Lite is used.