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

[cocoa]

Thank you RK, I 've read it previously.

My doubts are starting from release Jlink version 4.74 (the last one in .dmg format). In README.txt Segger wrote :

Requirements
============
libusb is no longer required.

So, I am inclined to think that starting from this version, libusb no longer used by Segger in OS X Jlink.

I've not installed any libusb on my mac.

But the main question here is why Jlink Lite cortexM-9 works fine without disabling CDC and Jlink OB on Nordic EK boards doesn't.

Any idea about ?

-c

[Ole Morten]

The J-Link Lite does not have a CDC interface and hence you don't need to do the module unload tweak that the Segger thread RK links to talks about.

I guess the removal of the libusb dependency may be because Segger have chosen to statically link with the library, instead of depending on it being on the system.

[cocoa]

Thank you Ole, that's solved the issue with OB version.

[RK]

Exactly - that's the question I asked at the start of my original reply below "does J-Link Like Cortex M have the CDC control and data endpoints", it doesn't (I just realised I have one and ran IORegistryExplorer on it) so the CDC driver doesn't see it.

As for the libusb dependency removal, from running a few tools on libjlinkarm I think they just rewrote it to use IOKit directly, which is what libusb does indirectly. Doesn't help however as still a device which has been exclusively obtained can't be used by anything else either via libusb or IOKit.

Only practical limitation here is you can't debug AND take serial output from one of the Segger modules with built-in CDC, which is vaguely annoying.

[cocoa]

@RK : very annoying ...