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.

[Nguyen Hoan Hoang]

I have used other jtag on OSX with CDC. Never have any issue with CDC. Only problem is with Segger, so arguably it is Segger bug. I have developed USB HID product in the past and I can say that Apple is very strict on USB descriptor. I remembered making a little mistake in one of the descriptor. OSX refuse to accept it although it is listed. But under Windows everything worked fine.