Segger J-Link, Clones, QuickFeather, Thoughts

To be perfectly clear, if a manufacturer provides good support for their product, you should buy from them, regardless of the cost. However, if you are scraping by on less than optimum wages, that is sometimes not possible. Period. In that case, people often turn to Chinese knock-offs.

In my experience, these clones do not work. You might be able to make them work, but you are opening yourself up to viruses, in many cases. (not all).

Segger.com provides the J-Link series of debuggers. For the level of support they give you, their $1000+++ price tag is reasonable. Especially if you are a corporation. In terms of wages paid to employees to fix problems, that price is usually better than the wages paid to engineers to solve the “must debug the board” problems due to the level of support that Segger provides. For you at home on the weekend, not so much. However, they have a solution (sort of).

If you are going to learn, then the J-Link Edu is the way to go. Unfortunately, that is out of stock everywhere I have looked. The J-Link edu mini is another choice, for about $60 to $90. Also out of stock. Also discontinued from several vendors. Segger does have the classroom pack J-Link edu mini in stock for over $700, so if you can get a few friends together for a group purchase, it might be an option.

If you can afford $500, the j-link base unit is a good possibility. That one is out of my price range.

At the current time, I am looking at working on the bricked QuickLogic QuickFeather (will be referenced as QF) board. For me this is a bit of fun, but it is also frustrating. I am also wanting to be able to debug *any* Cortex M Arm processor in the future. Segger is the primary choice if their cost was lower for the available units. Not sure I want to wait on “out of stock” and “discontinued” models, though.

If Segger provided a unit with *NO* support whatsoever for a price of $100 or so, I would be all over it. Fortunately, I have a legal Segger J-Link paid for by someone else, but I am unsure if it will work for this usage case since it is an unsupported V8 unit (but the firmware did update!). As soon as I get in the used adapter board from Ebay, I will find out.

Segger has, at wiki.segger.com an extensive “how to” set of instructions. One of them is for using VSCode. It is here: https://wiki.segger.com/J-Link_Visual_Studio_Code This page looks good. Just need an SVD file.

At https://github.com/Josfemova/eos-s3-rs/releases/tag/v0.1.0-alpha.0 there is an SVD for the QF board. Not sure how well it works. The YouTube video is here: https://www.youtube.com/watch?v=n6j7Qh_ql2s

The video for unbricking a QF board is here. Unbricking starts at 5:30 into the video. It requires a J-Link debugger: https://www.youtube.com/watch?v=Q5GIZUsXb3I

Fini

There are some J-Link OB boards that may be able to debug other Arm processors, but with VSCode, if you want references to peripherals to show up as other than raw addresses, you must have the right SVD files. The OB stands for “on board” and may be a way to get a cheaper J-Link debugger with some soldering. At https://github.com/posborne/cmsis-svd you will find a good list of SVD’s, but it is not exhaustive.

My QF is not yet working, so stay tuned.

Enjoy!