nrf52840dk Jlink OB USB cdc offsets 1 character

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

JONATHAN LL — Fri, 08 Jul 2022 12:39:05 GMT

OK thanks for the update. Go forth with a new ticket and and all your system info, then we can work on a solution there.
Regards,
Jonathan

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

blablub — Fri, 08 Jul 2022 06:11:24 GMT

Hi, thanks for your reply. Yes I also tried with an external hub, but still connected to the same AMD USB root controller. I have no other USB controllers on this specific machine. I will open a new Devzone Ticket for that.

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

JONATHAN LL — Wed, 06 Jul 2022 14:20:37 GMT

Hi blablub,

The issue might be a AMD issue, have you tried with an external powered USB hub?

And also, you can create a new Devzone ticket an link to this and we will try to find a solution with you.

Regards,
Jonathan

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

blablub — Tue, 05 Jul 2022 15:00:39 GMT

Hello rfleming, I use the same nrf52840dk board as you do. I even have the same rev. 2.0.1 on my table. VCOM was not usable when the issue occurs. (I have also other revisions which show the same issue).

While developing a product, I came across the same weird issues. When typing on the Zephyr shell, I was always lagging a character behind. No one else at my company experienced such issues and we use the boards extensively. This made developing scripts for VCOM unusable.

My findings are:

- I had only a single workstation which caused the problem every time I programmed a new image. Ryzen 5900x with a B550 board. Thinkpads were ok. The workstation was running for months and a cold boot eventually solved the issue.

- Flashing a new FW to the interface MCU resets the problem. But it was persistent until then.

- Never tried a rev. 3.0.0 board, but with rev. 3.0.0 the Atmel chip was replaced with an Nordic one. Maybe it helps.

- When I solder an external FTDI USB to UART adapter to the VCOM pins i have no issues.

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

JONATHAN LL — Tue, 22 Feb 2022 11:59:53 GMT

Sorry for the misunderstanding,

Yes the interface MCU has a bootloader on it, you can access it by holding the reset button while powering on the kit, does show up as a BOOTLOADER drive.

then its drag and drop.

Regards,
Jonathan

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

rfleming — Mon, 21 Feb 2022 23:05:43 GMT

Hi Jon,

In this case I was referring to programming the Atmel (Microchip) based ATSAM3U2CA - the IC chosen to use as the Jlink OB. I do believe this IC is supported by the Atmel ICE. However, I do also have an external JLink Pro that I could use to reprogram the Onboard Jlink OB as well. Though I don't know what the best way to go about it. Does the OB for instance, have a bootloader that I could simply upgrade/reflash its firmware over USB? Or is it better to reflash the chip entirely?

As you mentioned though if I don't come to a solution, I may just bypass the USB CDC convenience and use and external USB to Serial converter.

Cheers,

Ryan.

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

JONATHAN LL — Mon, 21 Feb 2022 13:29:17 GMT

Hi,

The Atmel ICE programmer will not work, as far as i am aware it does not support nRF products, so you will have to find some other tool to use it i belive.

It has ben asked before here: (+) nrfjprog supported SWD devices - Nordic Q&A - Nordic DevZone - Nordic DevZone (nordicsemi.com)

Can you try to use a different interface, bypass the debugger chip. Cutting SB50 to 53 will give you access to the MCU lines so you could use something else then the onboard programmer chip.

Regards,
Jonathan

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

rfleming — Mon, 21 Feb 2022 00:29:07 GMT

Unfortunately, I only have the 1x nrf52840dk. It is also the only Nordic kit I have that contains the onboard J-Link IC. All others require the external programmers.

Edit: Also note I have Atmel Studio installed with an Atmel ICE programmer, so if required I could simply write any new/old binary with that. If, of course the security IO is not set etc. I know this is a competitors IC of sorts, so it could be a bit of a conflict and I am happy to reach out to Segger directly if that's more appropriate.

RE: nrf52840dk Jlink OB USB cdc offsets 1 character

JONATHAN LL — Fri, 18 Feb 2022 15:42:44 GMT

Hi,

Do you have a different DK to test and probe to see if it acts differently? just to confirm that it might be a JLink OB IC issue.

I will look at this case and get back to you with more questions and answers, early next week.

Regards,
Jonathan