j-link issue if used with Nordic EK j-link OB

[cocoa]

I wish to inform Nordic about this issue with jlink OB used on EK boards when used in OS X environment.

J-link OB returns " Can not connect to J-Link via USB." and a CDC disabling is due to establish a connection.

But, if I use j-link Lite Cortex M there are no problems, the connection is ready without disabling CDC.

All firmwares are updated.

Not fatal but annoying .

-c

[RK]

Does J-Link Lite Cortex M have the CDC control and data endpoints as well as the Segger vendor-specific one? There's a number of posts on the Segger forum which explain that OSX, when it detects a CDC device, takes exclusive access to the entire device, including any of the endpoints which aren't CDC, that prevents libusb from accessing the Segger endpoint even though the CDC driver isn't using it.

This is arguably an OSX bug (well Segger argues it is) and I filed a bug report against it which I've not had a reply to yet.

If J-Link Lite Cortex M does have the CDC endpoints as well as the Segger one, I'm not sure how it's working, unless it presents itself as a composite CDC + Vendor device instead of one single interface, thus allowing OSX to attach the CDC driver to the CDC bit and leave the rest alone.

[cocoa]

I think is not a bug but an Apple security feature to block access to HID devices if not able to gain control at kernel level.

-c

[RK]

CDC is not a HID device.

I don't know whether it counts as a bug either, I just said that segger classified it as an OS X bug.

[cocoa]

You are right !! -c

[Ole Morten]

Could you expand a little on how you get this error, and what you can do to fix it? What exactly are you trying to do when you see this? Beware that I don't have a lot of experience using OS X, but I would be interested to see if I can reproduce it.

Also, it sounds as if this may be an issue with Segger's tools more than with our board. Have you been in touch with them about it?